How to Reset the CMOS

The CMOS (Complementary Metal-Oxide-Semiconductor) is a small memory space on a computer’s motherboard that stores the BIOS (Basic Input/Output System) settings. Resetting the CMOS can help resolve hardware compatibility issues, password locks, or improper system settings. This guide will outline the different methods to reset the CMOS on a desktop computer.

This method will reset any overclocking or XMP settings on the computer.

Precautions

1. Backup Your Data: Before you proceed, and if possible, make sure to backup all critical data. While resetting the CMOS shouldn’t affect your data in any way, it’s better to be safe.
2. Turn Off Power: Make sure to turn off your computer and unplug it from the electrical outlet.
3. Consult the Manual: If you have your motherboard’s user manual, consult it for specific steps to reset the CMOS.

Tools Needed

• Screwdriver (for opening the computer case)
• Flashlight (optional for better visibility)
• Tweezers or a jumper tool (for adjusting the CMOS jumper)

Method 1: Using the CMOS Jumper

1. Locate the CMOS Jumper: Open the computer case and find the CMOS jumper. This is usually a set of 3 pins on the motherboard, labeled something like “CLR_CMOS” or “CMOS_RST.”
2. Change Jumper Position: With the computer powered off and unplugged, move the jumper cap from its normal position covering two pins to the opposite two pins.
3. Wait: Wait for a few seconds (some recommend 10-30 seconds).
4. Return Jumper: Move the jumper cap back to its original position.
5. Restart the Computer: Close the case, plug the computer back in, and power it up.

Method 2: Removing the CMOS Battery

1. Locate the CMOS Battery: Open the computer case and locate the button-cell CMOS battery on the motherboard.
2. Remove the Battery: Carefully remove the battery using a flat tool, tweezers, or your fingernail.
3. Wait: Wait for approximately 5 minutes.
4. Replace the Battery: Put the battery back in its socket.
5. Restart the Computer: Close the case, plug the computer back in, and power it up.

Method 3: Through the BIOS Interface

1. Access BIOS: Turn on your computer and press the BIOS access key (often F2, DEL, or ESC) during the boot sequence.
2. Locate Reset Option: Navigate through the BIOS settings to find an option like “Load Optimized Defaults” or “Reset to Default.”
3. Execute Reset: Select the reset option and confirm.
4. Save and Exit: Save the changes and exit the BIOS.
5. Restart: The computer will restart with the default BIOS settings.