In PC hardware maintenance, which of the following is a standard and safe way to clear or reset a computer motherboard CMOS or BIOS password when it has been forgotten?

Introduction / Context:
The CMOS or BIOS password on a motherboard protects access to firmware settings, such as boot order, hardware configuration, and security options. If this password is forgotten, technicians must use a proper method to clear it without damaging hardware. This question tests your knowledge of standard procedures for resetting CMOS settings to factory defaults.

Given Data / Assumptions:

- The user has forgotten the BIOS or CMOS password.- We assume physical access to the computer and motherboard.- The goal is to clear the password safely, not to damage the system.

Concept / Approach:
On most motherboards, CMOS settings, including passwords, are stored in a small amount of memory powered by a battery. Manufacturers typically provide a clear CMOS jumper or similar mechanism to reset this memory. The safe procedure involves powering down the system, disconnecting it from mains power, and using that jumper or removing the CMOS battery for a short period to discharge and reset the CMOS memory. Actions that involve damaging components, rapidly pressing buttons, or formatting disks do not correctly reset the firmware password and may cause harm.

Step-by-Step Solution:
Step 1: Identify that option A describes powering off the computer, disconnecting the power, and using either a clear CMOS jumper or battery removal to reset BIOS settings.Step 2: Recognise this as a standard method recommended by motherboard manuals, usually with detailed instructions and safety notes.Step 3: Examine option B, which suggests formatting the hard disk. This only affects operating system files and user data, not BIOS passwords stored in CMOS memory.Step 4: Examine option C, which involves pressing the power button repeatedly. This is not a documented or reliable method to clear firmware passwords and can stress the hardware unnecessarily.Step 5: Examine option D, which suggests tampering with the power supply unit internally, something that is dangerous and unrelated to CMOS settings.Step 6: Examine option E, which suggests unplugging and reconnecting the monitor cable, which affects only video output and has no effect on password storage.Step 7: Conclude that only option A matches safe, standard practice for clearing CMOS passwords.

Verification / Alternative check:
Motherboard manuals and support websites describe clear CMOS procedures explicitly. They usually instruct users to set a special jumper to the clear position for a short time with power disconnected or to remove the CMOS battery briefly. After restoring the jumper and battery, BIOS settings revert to defaults, removing the old password. These step by step instructions confirm that option A reflects real world practice, whereas the other options do not appear in any official guidance.

Why Other Options Are Wrong:
Option B erases only the operating system and user data, leaving the BIOS password unchanged. Option C relies on random power button pressing, which has no designed link to CMOS reset. Option D is dangerous, violates safety rules, and still does not target the CMOS memory specifically. Option E affects only display connectivity, not internal firmware configuration. These methods are either ineffective or risky and should never be used for password clearing.

Common Pitfalls:
Some users incorrectly assume that reinstalling the operating system will reset everything, including BIOS settings. Others may try untested tricks found online that involve unsafe hardware manipulation. It is important to follow manufacturer documentation and to disconnect power before handling internal components. Always ground yourself to avoid static discharge and handle jumpers and batteries carefully.

Final Answer:
The standard safe method is to power off, disconnect power, and use the clear CMOS jumper or remove the CMOS battery to reset BIOS settings and clear the password, as described in option A.