How To Clear A Cmos

How to Clear a CMOS

If you are having issues with your computer’s BIOS settings or hardware, one of the first troubleshooting steps you can take is to clear the CMOS. Clearing the CMOS will reset the BIOS settings to their default state and can help resolve various issues. In this article, we will discuss how to clear a CMOS step by step.

What is CMOS?

Before we dive into the steps for clearing a CMOS, it’s important to understand what CMOS is. CMOS stands for complementary metal-oxide-semiconductor, which is a type of technology used in the manufacturing of computer chips. The CMOS chip in a computer stores the BIOS settings and other important configuration information.

Why Clear CMOS?

There are several reasons why you might need to clear your computer’s CMOS. One of the most common reasons is if you have made changes to the BIOS settings and are experiencing issues as a result. Clearing the CMOS will reset the BIOS settings to their default state and can help resolve these issues.

How to Clear a CMOS

Now that we’ve covered the basics, let’s move on to the steps for clearing a CMOS:

  1. Turn off your computer and unplug it from the wall.
  2. Open the computer case and locate the CMOS battery on the motherboard. It is usually a small, circular battery.
  3. Remove the CMOS battery from its socket. You may need to use a small screwdriver or other tool to gently pry it out.
  4. Wait for at least 5 minutes to allow the CMOS chip to discharge.
  5. Insert the CMOS battery back into its socket.
  6. Close the computer case and plug the computer back into the wall.
  7. Turn on your computer and enter the BIOS setup utility. The BIOS setup key may vary depending on your computer’s manufacturer, but it is usually F2, F10, or Del.
  8. Verify that the BIOS settings have been reset to their default state.

And that’s it! You have successfully cleared your computer’s CMOS.


Q: Will clearing the CMOS delete my files?

A: No, clearing the CMOS will not delete any files from your computer’s hard drive. It will only reset the BIOS settings to their default state.

Q: Do I need to clear the CMOS if I upgrade my hardware?

A: It is not always necessary to clear the CMOS when upgrading hardware, but it can be a good idea to do so if you are experiencing issues after the upgrade.

Q: What do I do if clearing the CMOS doesn’t fix my issue?

A: If clearing the CMOS does not resolve your issue, there may be a deeper underlying problem with your computer’s hardware or software that requires further troubleshooting.


Clearing the CMOS can be a simple and effective troubleshooting step for resolving issues with your computer’s BIOS settings or hardware. By following the steps outlined in this article, you can easily clear your computer’s CMOS and get back to using your computer without any issues.