Chapter 2. Laptops, Part 2
This chapter covers the following A+ 220-1001 exam objectives:
• 1.2 - Given a scenario, install components within the display of a laptop.
• 1.3 - Given a scenario, use appropriate laptop features.
In this chapter, we get into the laptop display and some of the common features of a laptop. It’s important to understand the types of displays available to you, as well as what an inverter is, and how to handle it properly. You’ll also learn about additional components such as Wi-Fi antennas, webcams, touchscreens, and special function keys. We’ll close it out with add-on connectivity and security for laptops. Let’s go!
1.2 - Given a scenario, install components within the display of a laptop.
ExamAlert
Objective 1.2 focuses on the following concepts: LCD, OLED, WiFi antenna connector/placement, webcam, microphone, inverter, and digitizer/touchscreen.
Note
The CompTIA A+ objectives list important concepts that you need to know for the exam, but the list is not finite. By this, I mean that there might be other associated technologies that are not listed, but which you might be tested on. So, at times, I add content to this book that goes further than the listed objectives. Be ready to study beyond the objectives to fully prepare for the exam, and for the real world.
For the exam, you should understand the differences between the various laptop display types, including: LCD, LED, and OLED. Going further, you want to know the basics about the display’s inverter and digitizer technology. Finally, be sure to know how other components are installed that might be located in the display area of a laptop; for instance, webcams, microphones, and Wi-Fi antennas.
Display Types
A laptop might use one of a few types of displays, depending on the age and the price of the laptop. These include LCD, LED, and OLED.
• LCD: The liquid-crystal display (LCD) is a flat-panel display that consists of two sheets of polarizing material surrounding a layer of liquid crystal solution. It connects to the motherboard by way of a flex ribbon cable, or an all-in one power/signal cable, and gets its power from an inverter board. Most of today’s LCD screens are thin-film transistor (TFT) active-matrix displays, meaning they have multiple transistors for each pixel. These transistors are contained within a flexible material and are located directly behind the liquid crystal material. In general, LCDs generate a small amount of heat, and cause little in the way of interference and emissions. However, they use more electricity than newer types of displays because they utilize a high-powered bulb; quite often, a cold cathode fluorescent lamp (CCFL).
• LED: Light-emitting-diode (LED) monitors utilize two-terminal electronic components known as diodes to display images. These diodes are red, green, and blue (RGB); the “primary” colors when it comes to computer monitors. They use less power than traditional LCDs and are therefore more efficient. LED monitors use a different backlight than traditional LCD monitors. Whereas the older LCD monitors use a CCFL as the illumination source, LED monitors use light-emitting diodes, which release photons; this process is known as electroluminescence. It is so much more energy efficient that you will find many hybrid designs known as LED-backlit LCDs. In that case, we are not using a CCFL, and instead utilize diodes but with an LCD screen.
• OLED: OLED stands for organic light-emitting diodes. The main advantage of OLED over LED is manufacturing cost; OLEDs can be printed onto just about any substrate using simple printing processes—and they can be incredibly small (even one per pixel), all lighting individually. The technology uses an organic compound to emit light in response to an electric current. OLED displays have the best black levels, but you might opt for LED if you are more concerned with brightness and some other specifications.
Inverter and Backlight
A typical laptop’s LCD display incorporates a backlight and an inverter. The backlight is a bulb; for example, a CCFL. It emits light through the screen so that you can see the images that the computer is attempting to display. The inverter, or more accurately the screen inverter, is a device that converts direct current (DC) that comes from the motherboard into alternating current (AC) to be used by the display’s backlight. This section focuses on LCDs because LEDs (and OLEDs) don’t need an inverter—they are DC only by design—and don’t use a CCFL or similar lamp.
ExamAlert
Know that a screen inverter’s job is to convert DC voltage from the motherboard into AC voltage to be sent to the backlight.
The video display in laptops is integrated; however, while being a main feature of the portability of laptops, it can be a point of failure as well. Minor issues such as intermittent lines on the screen suggest that the display cable needs to be reconnected or replaced. However, complete display failures suggest a worse problem that will take longer to repair. Aside from a damaged screen, LCD display failures can be broken down into a couple categories: a damaged inverter or a worn out backlight.
Damaged Inverter
To review, on a laptop with an LCD-based screen, the LCD is usually lit by a CCFL (basically a bulb); it is that LCD backlight which requires AC power. The backlight is driven by a high-voltage inverter circuit. Because the inverter runs at high voltage, and possibly at high temperatures, it is prone to failure. If the inverter fails, the display will go dark; however, an external monitor should work properly. Another possibility is that the backlight has failed. You can verify if it is an inverter/backlight issue by shining a flashlight directly at the screen (best in a dark room). When you do this, you should be able to make out the operating system! This means that the display is getting the video signal from the motherboard and the problem, most likely, is indeed the inverter or the backlight. If the display’s cable that connects the LCD to the motherboard was loose or disconnected, or if the video adapter failed, then nothing would show up on the screen at all. The inverter circuit is usually situated on its own circuit board. The inverter often has two connectors: one for the high-voltage connection that leads to the power source and one for a cable that connects to the display. Disconnect these and carefully remove the inverter. As always, hold circuit boards by the edges and try not to touch any actual circuits or chips.
ExamAlert
Warning! The inverter should not be handled if the laptop is on! Be sure to turn off and unplug the laptop and remove the battery before removing an inverter.
Worn Out Backlight
A laptop’s backlight usually lasts a long time. However, at some point the lamp starts to wear out. You might notice a dimmer screen than before, or a reddish/pinkish hue to the screen, or maybe a loss of color. All of these things indicate the possibility of a worn-out lamp.
To replace either the inverter or the lamp, you need to disassemble the display. This usually means removing a screen bezel, and taking the screen out, which gives way to those items. Be ready to have mobile device tools on hand, especially a thin but strong plastic shim. Consider purchasing a pry tool repair kit that includes a variety of shims, prying tools, and so on. Don’t forget to keep a variety of small screwdrivers on hand.
Note
As you can guess, LED and OLED screens do not suffer as many failures as CCFL-based LCDs do, mainly because LEDs and OLEDs do not incorporate (or need) an inverter or a lamp. Consider that when making laptop purchases.
Digitizers and Touchscreens
A touchscreen—also known as a digitizer screen—is a screen that allows for tapping or writing on the screen. Many allow users to simply use their finger, while others also allow for the use of a stylus. A stylus is a writing tool, usually a thin plastic “pen” type of device used to take the place of a mouse; it enables you to tap and “write” on the digitizer with great accuracy.
These methods are widely used in smartphones, tablets, handheld computers, Chromebooks, and some laptops. For example, usually, when you sign for a package from a shipping company, you sign with a stylus on a touchscreen/digitizer. This takes the place of pencil and paper.
More accurately, the digitizer is the device that converts tapped or written impulses (analog) on the screen into instructions (digital) for the operating system to follow.
Removal of a touchscreen is much the same as a regular screen, as described in Chapter 1. There will be some disassembly required: screen bezels, plastics, and so on will have to be removed before the screen can be unscrewed and disconnected.
Note
Be prepared to have very small screwdrivers available. Laptop and mobile device repair kits often come with these types of screwdrivers. But, also be prepared for more “proprietary” types of screws that require fewer common screwdrivers.
There are also digitizer overlays that can be added on to a laptop screen. Generally, these touch screen kits are strapped on to the display with Velcro and connect via USB. Be ready to install custom drivers and perform touch screen orientation and/or calibration.
Webcam and Microphone
Webcams are great for communication but sometimes they fail, and in some cases are considered a security vulnerability. In the case that the webcam has to be replaced, or just removed altogether, you can follow a few simple steps. First, employ antistatic measures. Then, remove the bezel from the display. The webcam module should then be visible above the display screen. Often, it is just connected with a small plug, and no screws or attachment of any kind. Next, carefully disconnect it with your shim or other thin prying tool (non-metal), and place it in an antistatic bag, and label it for later use. Hold on to any tape or sticky material that keeps the webcam in place. Next, replace it with an identical part. Be very careful when connecting the power for the new webcam, the plug is often delicate. Use, or re-use tape to fasten the webcam in the right spot (if necessary). Then, attach the bezel to the display once again. Finally, test the webcam’s video and audio with an application such as Windows’ built-in Camera program.
Some people use tape to cover the webcam for security or privacy purposes, but depending on the policies of your organization, this might not be enough, and you will have to remove it altogether. Some companies offer filler items to fill the gap where the camera lens normally goes.
A laptop might have a function key that can disable the webcam. It can also be disabled in the operating system, so be sure to check those before replacing the webcam.
The microphone on a laptop is often part of the webcam module, for example to the left of the lens. So, removing the webcam module removes the microphone. The microphone could also be disabled in the operating system. For example, in Windows you would do this in the Recording tab of the Sound dialog box. As mentioned, some people use tape to cover the webcam, and the microphone openings as well; however, depending on the type of tape, it might muffle the recorded sound, but not eliminate it. Once again, for security purposes, it is better to disable the webcam altogether, or remove it.
ExamAlert
Know where to find the webcam and microphone within a laptop display, and know how to disable them for the exam.
Some companies opt to disable the webcam (and associated microphone) and instead use external USB-based webcams to achieve better security as well as better performance, while allowing the user to physically disconnect the webcam when it is not in use.
Wi-Fi Antenna Connector and Placement
Wi-Fi antennas are used to connect to a wireless network, also known as a wireless local area network (WLAN). Wi-Fi antennas can be found inside the laptop as well as externally. If the antenna is inside the laptop, it will usually be some type of module; either an M.2 card (as shown in Figure 2.1), or a PCI Express Mini Card (also known as a Mini PCIe card).
Figure 2.1 A typical internal Wi-Fi module using the M.2 form factor
ExamAlert
Be able to identify M.2 and Mini PCIe cards by name and by sight for the exam.
Usually, this module can be identified quickly by removing the bottom cover. It is often easily found, is connected to a slot, and is attached with either one screw (for M.2) or two screws (for Mini PCIe). M.2-based cards have up to 67 pins and might use the 2230 standard (22 x 30 mm) or the 1216 standard (12 x 16 mm), among others. The one in Figure 2.1 uses the 2230 standard. Full size Mini PCIe cards are 30 x 50.95 mm and use a 52-pin edge connector. There are also half mini cards that are the same width, but are 26.8 mm long. This is also known as “half height”, though this name isn’t quite accurate. Both of these are about half the width of the older Mini PCI standard.
Be careful when installing an M.2 or Mini PCIe card, the contacts can be easily damaged. Place even pressure on both sides and press the card into the slot evenly so it goes in straight without any side-to-side movement. If a Wi-Fi antenna cable already exists in the laptop, re-use it by connecting the wire ends to the contacts on the card; usually there is two, one for Wi-Fi, and one for Bluetooth (BT). If there is no antenna, install a new one, and route it through the laptop hinge and around the display as far as it can go. The longer the antenna, the better the reception.
Of course, external Wi-Fi adapters can be used, connecting to USB or an RJ45 port. If that is the case, then the antennas (if there are any) can be pointed in the direction that you desire. Or, the adapter can be moved from one USB port on one side of the laptop to another USB port on the other side. Just remember to consider using USB 3.0 or higher (blue ports or better). Also, keep the module away from any sources of interference. If it has actual antennas that you can move, first attempt a 90 degree angle, and then if that doesn’t work, experiment! However, many external Wi-Fi modules that connect via USB are small self-contained devices and the actual antenna is embedded inside. So, the choice of USB port is really your only option in that scenario when it comes to antenna placement.
Wi-Fi transmissions rely on the IEEE 802.11 standards including 802.11ac, n, g, and b (going from fastest to slowest). We’ll discuss those protocols more in Chapter 6, “SOHO Networks and Wireless Protocols”.
Every Wi-Fi adapter has its own unique media access control (MAC) address, also known as a MAC ID. This identification number is usually printed on a sticker on the Wi-Fi adapter, and it is programmed into the ROM of the adapter. It differentiates the Wi-Fi adapter from all other network adapters on your network and around the world. Regardless of the type of network adapter, the MAC address is a 48-bit number, described in the hexadecimal numbering system. For example: 68-05-CA-2D-A4-B3. The number is also referred to as a physical address in the Windows command-line. If you have an internal Wi-Fi adapter, you can find out the MAC address in Windows by typing ipconfig /all in the Command Prompt or the PowerShell. (In macOS or Linux you can use ifconfig or ip a.) We’ll discuss the MAC address more in Chapter 6, “SOHO Networks and Wireless Protocols.”
Cram Quiz
Answer these questions. The answers follow the last question. If you cannot answer these questions correctly, consider reading this section again until you can.
1. Which kind of video technology do most laptop LCDs use?
A. TFT Active Matrix
B. Passive Matrix
C. OLED
D. MAC ID
2. Which of the following uses an organic compound that emits light?
A. TFT Active Matrix
B. IPS
C. OLED
D. LCD
E. LED
3. Which of the following are two possible reasons why a laptop’s LCD suddenly went blank with no user intervention? (Select the two best answers.)
A. Damaged inverter
B. Damaged LCD
C. Burned-out backlight
D. Incorrect resolution setting
4. Which of the following allows us to access a WLAN?
A. LED
B. Webcam
C. Digitizer
D. Stylus
E. Wi-Fi card
Cram Quiz Answers
1. A. TFT active-matrix displays are the most common in laptops that use LCDs. Passive-matrix screens have been discontinued, but you might see an older laptop that utilizes this technology. OLED technology is a newer and different technology that is not based on TFT displays, but instead uses emissive display technology, meaning that each dot on the screen is illuminated by a separate diode. OLED displays can however be passive-matrix or active-matrix controlled. The MAC ID is the hexadecimal address associated with a network adapter, such as a Wi-Fi adapter or network card.
2. C. OLED (organic light emitting diode) displays use an organic compound or film that emits light. TFT active-matrix implies LCD, and neither of them use organic compounds the way OLED does. In-plane switching (IPS) is a type of LCD technology that increases the available viewing angle compared to older technologies such as twisted nematic (TN) matrix LCDs. However, IPS is generally considered inferior to OLED screens when it comes to brightness and contrast ratio when viewed from an angle. LED screens use a film and diodes, but not organically in the way that OLED does, and not at such a small size.
3. A and C. A damaged inverter or burned-out bulb could cause a laptop’s display to go blank. You can verify whether the LCD is still getting a signal by shining a flashlight at the screen. A damaged LCD usually works to a certain extent and will either be cracked, have areas of Windows missing, or show other signs of damage. An incorrect resolution setting can indeed make the screen suddenly go blank (or look garbled), but that scenario will most likely occur only if the user has changed the resolution setting—the answer specifies with no user intervention.
4. E. A Wi-Fi card, also known as a Wi-Fi network adapter, allows us to connect to a WLAN (wireless local area network) which is essentially another name for a Wi-Fi network. LED is a type of display. A webcam is used to communicate visually and audibly with others, or to record oneself. A digitizer is the device that converts tapped or written impulses on a screen into digital information that the operating system can use. A stylus is a writing device used with a digitizer or touchscreen.
1.3 - Given a scenario, use appropriate laptop features.
ExamAlert
Objective 1.3 focuses on the following concepts: Special function keys, on/off keys, docking stations, port replicators, physical laptop locks, cable locks, and rotating/removable screens.
We’ll close out the laptop portion of this book with laptop features. A laptop will have many special function keys. Generally, these are secondary functions of the F1 through F12 keys, but in addition, they can be altogether separate buttons on the top of the laptop. These allow us to enable and disable many of the important features of a laptop such as: Wi-Fi, Bluetooth or GPS; enabling/disabling the touchpad; and adjusting the brightness and volume. Docking stations and port replicators allow us to turn a laptop into more of a workstation, adding monitors, keyboards and mice, as well as network connectivity and storage capabilities. A user might have a need for a more adjustable laptop, for instance one that has a screen that rotates, flips over, or is removable. Or perhaps, the user is interested in physical security. This section covers all of these laptop features and functionality that go beyond the core physical devices.
Special Function Keys
Some laptops have keyboards similar to the 101-key keyboard found on a PC and include a numeric keypad; these laptops are larger than most and are known as desktop replacements. However, most laptops are designed with a small form factor in mind, and this means a smaller keyboard. For example, the keyboard in Chapter 1, Figure 1.1 has 86 keys. But as shown in Figure 2.2, a user has the option of using the Fn key. The Fn key (Function key) is a modifier key used on most laptops. This is designed to activate secondary or special functions of other keys. For example, in Figure 2.2, the F12 key has the secondary function that turns the wireless connection on or off, but only if you press the Fn key at the same time you press the F12 key. To make it easier to read, Figure 2.2 breaks up the Fn key and the F1-F12 function keys, so you can see each of them better. But remember that the Fn key is usually toward the lower left hand corner of the keyboard (in between the Ctrl and Windows keys), and the function keys (F1-F12) are situated at the top of the keyboard.
Figure 2.2 Typical function keys and their tasks
Using this method, much more functionality can be incorporated into the keyboard without the need for additional keys. This idea has since grown to include all kinds of controls (for example, using media player controls (play/pause/fast forward/rewind); putting the computer to sleep; and enabling Bluetooth, the keyboard backlight, the touchpad, GPS, cellular connections, airplane mode; as well as screen orientation, and a variety of other functions, including enabling an external monitor). On this laptop, the F4 key seconds as a display toggle between the built-in display and an external monitor. Take a look at Figure 2.2 and attempt to identify what each of the function key images represent.
ExamAlert
Use the Fn key in combination with F1-F12 function keys to configure many things including media options, Wi-Fi access, brightness, the touchpad, and an external monitor.
But all this is up to the manufacturer and any key can be given a secondary function. That enables things like the numeric keypad, and the number lock key, which might be abbreviated as Num Lock, or num lk. (This could also be an individual key.) Sometimes, users forget about the Num Lock key, and when they try to type, strange garbled code comes out! This is because the numbers are sharing keys used by letters and symbols. Simply press the Num Lock key once to fix the problem. This is also common if the user works with an external keyboard at the office and disconnects it when leaving the office. However, today’s operating systems and programs are pretty good at sensing things such as an enabled Num Lock or Caps lock key.
ExamAlert
If available, press the Num Lock key to enable/disable the numeric keypad on a laptop. If the Num Lock indicator light is on, then the numeric key is enabled.
Note
Sometimes a laptop will have separate buttons near the power button or elsewhere that aren’t considered part of the regular function keys. These might be called special keys, special buttons, hot buttons, hotkeys, or corner keys. They might not function properly without a special keys driver. This driver can be separate from the main keyboard and touchpad drivers. It is a setup that is more common in older laptops. It can be a bit confusing because the F1-F12 keys are also referred to as special function keys sometimes. Be ready for the word “special” to be used with either type.
External Monitors
Most laptops have the capability of sending video signals to an external monitor. Some people refer to this technology as screen switching and/or extending the display. Most laptops come with an external connection (for example, HDMI or DisplayPort) for a second monitor or for a projector. When this monitor is plugged in, it can be enabled by pressing the display toggle key (otherwise known as the secondary monitor button). On the laptop used in this chapter, this can be done by pressing Fn + F4 simultaneously. However, on other brands of laptops, this key might be a different key than F4. The icon on the key usually looks like an open laptop with a monitor to its right. Normally, you have several options: display the desktop to the laptop, display the desktop to the external monitor, display a copy of the desktop to both screens, or “extend” the desktop across both monitors. These last two options are also known as using dual displays. In addition to using the display toggle key, you can configure your video for any of these scenarios in Windows, macOS, or Linux, which we’ll discuss later in the book.
If the external monitor won’t display anything, make sure that the cable is firmly connected to the external port, verify that the external monitor is plugged in and on, and then try cycling through the various video options by pressing the button several times, waiting a few seconds each time. Make sure you are holding down the Fn key while doing so. Finally, restart the computer if necessary. This can get a little trickier when you are using a projector as the second display. Sometimes, the projector might need time to warm up or might need to be configured via its on-screen display (OSD). You might also need a video adapter if your laptop and projector’s ports don’t match up. Identify the projector’s ports, and locate the projector’s documentation for more details.
ExamAlert
If nothing shows up on an external display, then try cycling through the different display modes by using the Fn key and the appropriate special function key.
Docking Stations and Port Replicators
The docking station expands the laptop so that it can behave more like a desktop computer. By connecting the laptop to the docking station and adding a full-size keyboard, mouse, and monitor, the user doesn’t actually touch the laptop any more except perhaps to turn it on. Some laptops can hot dock, meaning they can connect to the docking station while powered on. The docking station recharges the laptop’s battery, and possibly a second battery, and has connections for video, audio, networking, and expansion cards. Docking stations might even have an optical disc drive, additional hard drive, and additional display and USB ports; it all depends on the brand and model. If all these extras aren’t necessary, a user might require only a port replicator, which is a similar device but it has only ports (for example, video, sound, network, and so on). Sometimes these are just referred to as docking stations as well.
ExamAlert
Note the difference: A laptop is placed or “docked” into a docking station. However, a port replicator is connected to the laptop simply to provide additional ports.
Rotating and Removable Screens
Some laptops come with rotating screens that not only open up, but can swivel from side to side. Other laptops (and some mobile devices) have screens that are removable altogether. While this can be great for the user that needs more mobility and/or the ability to use the device as a tablet, the probability of failure increases. In fact, any moving or connecting parts in any device will increase the chance of failure; such as a blank display, or intermittent video issues. One of the things you can check is the connection itself. Perhaps it is dirty and needs to be blown out with compressed air, or perhaps a pin or connector is bent or damaged. In some cases, these ports can be fixed or replaced, but in many cases they have to be repaired by an authorized repair center. More reason to have good warranties and possibly insure the laptops in your organization. Remember to educate users on how to gently connect displays, and how to work with them properly to avoid these problems in the future.
While some laptops do incorporate these types of technologies, it is also common to see them integrated with mobile devices that aren’t necessarily classified as laptops—and might be classified as hybrid laptops, or simply mobile devices. These devices can have rotating screens, or displays that can be folded completely over, or ones that can be removed altogether. In some cases, these devices are displays to which you can connect a keyboard. So, the lines get a bit blurred. We’ll discuss other mobile devices such as tablets, smartphones, and so on, in Chapter 3 and 4.
Securing Laptops with Cable Locks
One way to physically secure a laptop is to use a cable lock. This works in a similar fashion to a bicycle lock (if you have ever used one). It consists of a very strong cable that is difficult to cut through—often galvanized, and multi-stranded steel—with a lock on one end and a loop on the other. This allows the user to secure the laptop in a variety of ways, for example to a table, desk, and so on. Some companies incorporate metal loops or eye bolts near workstations to use with the cable lock for increased security. The lock itself will often adhere to lock picking protection standards, and is usually a tubular cam lock, which can be keyed individually, or keyed for use with a master key. Many laptops come with a security slot to be used with cable locks; the tubular lock is inserted into the slot and turned 90 degrees to lock it or unlock it. This, of course, is only one anti-theft solution for laptops, but it is one that is commonly used by organizations, corporations, and individuals.
Note
Know that you can increase the security for your laptop but there is never a 100% secure solution, because any security technique can be bypassed given time, persistence, and ingenuity. So, a cable lock can help, but don’t rely solely on that, or any other single security precaution.
Cram Quiz
Answer these questions. The answers follow the last question. If you cannot answer these questions correctly, consider reading this section again until you can.
1. Which of the following keys should you press to enable a secondary display on a laptop? (Select the two best answers.)
A. Fn key
B. Caps lock key
C. Num Lock key
D. Special function key
E. Insert key
2. When a user types, a laptop’s screen displays letters and numbers instead of only letters. What should you check first?
A. Fn key
B. LCD cutoff switch
C. Num Lock key
D. Scroll Lock key
3. You are required to install an anti-theft solution for a customer’s laptop. Which of the following should you perform?
A. Install a docking station
B. Install a cable lock
C. Install Windows
D. Configure a password in the BIOS/UEFI
E. Use a port replicator
4. You are helping a project manager with a presentation using a laptop which feeds video to a projector. During your tests, the projector’s image begins to flicker. The laptop’s display does not have any problems. You attempt to change the resolution on the laptop, but the issue continues. Which of the following should you do next?
A. Change the projector settings.
B. Check the connectivity of the video cable.
C. Change the aspect ratio of the laptop.
D. Check the connectivity of the power cable.
Cram Quiz Answers
1. A and D. To enable a secondary, or external, display on a laptop you would use the Fn key (called the function key) and a special function key, for example F3 or F4, whichever one that corresponds to screen switching. It’s this combination of keys that allows you to make use of displays plugged into HDMI or other ports on the laptop. The caps lock key enables a user to type in all uppercase letters. The number lock key (if available) turns on the numeric keypad (if the laptop has one). The insert key is often used by programs such as word processors in one of two modes: overtype; where anything that is typed is written over any existing text; and insert mode, where typed characters force the existing text over.
2. C. The Number Lock key (Num Lock) can enable or disable the numeric keypad. This might be necessary if the user inadvertently turned it on or disconnected an external keyboard from the laptop. Some laptops require you to press Ctrl+Num Lock to enable or disable the numeric keypad. Laptops are usually color-coded (for example, white options might require the Ctrl key and blue options might require the Fn key). In this scenario, pressing the Function (Fn) key is not necessary when pressing the Num Lock key. The LCD cutoff switch is used to turn off the bulb that lights the LCD. The Scroll Lock key is not often used but it is meant to lock any scrolling done with the arrow keys.
3. B. Install a cable lock to increase the security of a laptop and decrease the chances of theft. Docking stations and port replicators offer increased functionality for a laptop but do not increase security; the laptop can be easily disconnected from them. Installing Windows is not an anti-theft solution, nor any type of security precaution. Configuring a password in the BIOS/UEFI is a good security practice, but it will not help avoid theft. However, if the laptop is stolen, a user password (and administrator password) that is configured in the BIOS can help prevent a person from accessing what is on the laptop.
4. B. Check the connectivity of the cable. If it is flickering, chances are that the cable is loose, or the cable’s quality is lacking. Screen flicker is more common with VGA cables, but it can happen with just about any connection. Remember, always check the basic stuff first: connectivity, power, and so on. It is unlikely that the projector settings will make a difference based on this particular problem. You cannot change the aspect ratio by itself on most laptops, however, when you change the resolution (which was already done in the question) you might be changing the aspect ratio as well, depending on the resolution selected. If the power cable was loose or damaged, it would probably result in more than just screen flicker; the projector might power off and power back on, which would prevent the image from being displayed for at least several seconds while the projector powers back up. Great job so far! Two chapters down!