Basic computer operations (hardware and software)

Lossless compression preserves all information needed to reconstruct the original data exactly after decompression. It is therefore appropriate for text documents, spreadsheets, program files, and other data where even a small alteration could matter. Option A describes a situation suitable for lossy compression, which deliberately discards some information. Options C and D are unrelated device actions, so option B is correct.

Malware is software intentionally created or misused to damage systems, steal information, spy on users, disrupt work, or perform actions without proper permission. A normal application is generally designed to provide an intended service to the user. Thus option A states the key difference; the other choices are either unrelated, factually false, or absolute.

Antivirus definition files contain detection information, often called signatures or rules, for recognising malicious files and behaviours. Threats change constantly, so updates help the antivirus identify newer malware that an old database may miss. Option B is correct. Updating definitions does not alter screen colour, storage capacity, or mouse speed.

Real-time protection continuously watches relevant files, downloads, programs, and system activities as they are opened or executed. If suspicious behaviour is detected, it can warn the user, block the action, or quarantine the item. Option C is correct. Printing, monitor brightness, and physical weight are unrelated to antivirus protection.

An unknown attachment can contain malware, phishing content, or a harmful script, even when its name appears familiar. The safe process is to verify the sender through a trusted channel, inspect the message carefully, and let security software scan the file before opening it. Therefore option D is correct; forwarding, renaming, or disabling antivirus increases risk.

Installation permissions describe the resources an application may access, such as files, contacts, a camera, microphone, location, or network services. Reading them helps a user decide whether the requested access is necessary and trustworthy. Option A is correct. Printer colour, computer height, and mouse size are not purposes of permission settings.

Software compatibility means that a program can work correctly with the computer’s operating system, processor, memory, storage, and sometimes connected hardware. Checking the stated requirements before installation helps prevent failure, errors, or poor performance. Option B is correct. Cleaning a screen, changing file colours, and reducing printer weight are unrelated to compatibility.

Some software installations add or replace system files, services, or device drivers. A restart closes programs that may still be using older versions and reloads the updated components so they can operate correctly. Option C is correct. Restarting does not enlarge a monitor, load printer paper, or rename a folder, although saving open work first is important.

Computers use vents and fans to move warm air away from components. Dust blocking these openings reduces airflow, so heat can build up around the processor and other parts. The result may be slower performance, unexpected shutdowns, or hardware damage; therefore option D is correct. Dust cannot increase storage, organise files, or make internet access free.

A CPU may use thermal throttling when its temperature becomes too high. It deliberately lowers its clock speed and may reduce performance so that less heat is produced, protecting the processor and nearby components from damage. Therefore, option A is correct. The other choices are unrelated: CPU throttling does not increase printer speed, compress files, or strengthen an internet signal. Improving airflow or removing dust addresses the underlying cooling problem.

Changing one setting, cable, driver, or component at a time follows a controlled troubleshooting method. If the problem disappears after that single change, the technician can reasonably connect the result with the change and record what solved it. Multiple changes made together hide cause-and-effect relationships and may create new problems. Thus option B is correct; the other choices describe effects unrelated to systematic diagnosis.

If the operating system and other applications continue working, the computer has not experienced a complete power failure or total system shutdown. The evidence therefore points first to a fault in the particular application, such as corrupted settings, an incompatible update, or an application bug. Option C is the most reasonable conclusion, although further testing is needed. A failed monitor or keyboard would not normally close one program.

A device driver is software that enables the operating system to communicate with and control a particular hardware device. If the driver is missing, outdated, incompatible, or disabled, the newly connected device may not be recognized correctly. Thus option A is the appropriate software check. Screen brightness, desktop wallpaper, and paper loading concern unrelated settings or printer operation and would not explain general device detection.

In common desktop operating systems, dragging an item while holding the Control key changes the drag action from moving to copying. The original folder remains in its first location, while an equivalent folder is created at the destination. Thus, option C is correct. Deletion, compression, and automatic renaming require different commands and do not normally result from this key combination.

The governing concept is non-volatile memory. Firmware or basic startup instructions must remain available even when the computer is switched off, so they are traditionally stored in ROM or ROM-based firmware. Option D is correct. RAM and cache are volatile working memories, while virtual memory uses storage to extend RAM temporarily; none is the normal permanent location for startup firmware.

Main memory, usually RAM, temporarily holds the instructions and data needed by active programs. If many programs run simultaneously and RAM becomes insufficient, the system may use slower storage as virtual memory, causing noticeable slowdown. Option B is therefore correct. Monitor colour, printer paper, and mouse-cable length do not indicate a need for more RAM.

A standard user account operates with limited permissions, so programs or users have less ability to install software, change system settings, or modify protected files without authorization. This follows the cybersecurity principle of least privilege, making option A correct. It does not double processor speed, remove every virus automatically, or eliminate electricity use; those claims confuse account permissions with unrelated functions.

An installer may replace system files, add drivers, register services, or update settings that are currently in use. A restart reloads those components and allows the operating system to complete the installation safely. Therefore, option B is correct. Measuring a monitor, charging a mouse, or changing a document font is not a normal technical reason for an installation restart request.

Software obtained from an untrusted website or unknown person may be modified to include malware such as a virus, spyware, ransomware, or a hidden back door. Installing it can expose files, damage the system, or allow unauthorized access. Therefore, option B is correct. Monitor weight, keyboard size, and hard-disk color cannot be changed by an installer in the stated sense.

Firmware is specialized software stored in non-volatile memory associated with a hardware device. During startup, it provides low-level instructions that initialize and control hardware before the operating system takes over. Therefore, option D is correct. Presentation software, spreadsheets, and web browsers are application programs that run after the system has started and do not perform this initial hardware-control role.

The governing concept is software maintenance. Application updates commonly repair programming bugs, close known security vulnerabilities, improve compatibility, and sometimes add features or performance improvements. Option B identifies the most important general reason because unpatched weaknesses can expose data or systems to attacks. Updates do not change the computer’s physical weight, convert a keyboard to wireless operation, or alter monitor dimensions, so A, C, and D are unrelated.

The governing concept is open-source licensing. Open-source software provides access to its source code under stated license conditions, which may permit studying, modifying, and redistributing it within those conditions. Option C is correct. Open source does not mean that modification is forbidden, that the program runs on only one computer, or that it needs no operating system. It also does not necessarily mean completely free of cost.

The governing concept is systematic troubleshooting. A blue error screen may result from a faulty driver, incompatible hardware, or another system-level fault. Recording the exact error code and checking recent changes provides evidence about the cause, so option A is correct. Changing wallpaper, document fonts, or a mouse pad does not investigate operating-system or hardware failures.

The governing concept is device-driver communication. A printer driver translates the computer’s print instructions into commands the printer understands. If the driver is incorrect, outdated, or corrupted, characters may be missing, distorted, or printed incorrectly; therefore, option B is correct. The monitor stand, keyboard colour, and extra mouse buttons have no meaningful connection with printer data interpretation.

The governing concept is access control. A permission system assigns rights to users or programs, such as reading, writing, modifying, or executing a file. By checking these rights, the operating system prevents unauthorised access or unwanted changes. Therefore, option C is correct. Processor speed, paper quality, and monitor resolution are unrelated to file and resource permissions.