What is CMOS and How to Reset

What is CMOS and How to Reset

What is CMOS

CMOS (Complementary Metal-Oxide-Semiconductor) is a type of technology used in electronic devices such as computers, smartphones, and digital cameras. It is a type of semiconductor that allows for low power consumption, high speed, and compact size.

In a computer, the CMOS is a small battery-powered chip that stores critical system information such as the date, time, and hardware configuration. It is used to keep track of the BIOS (Basic Input/Output System) settings, which control how the computer interacts with its hardware components. Without the CMOS chip, a computer would not be able to start up correctly because it could not store that very basic data.

Sometimes, the chip may become corrupted, leading to errors in the system’s hardware configuration. This can result in issues such as incorrect date and time, error messages during startup, and system crashes. To fix these issues, you may need to reset the CMOS chip.

Resetting the CMOS chip involves clearing all the data stored in it, including the BIOS settings. This will revert the system to its default hardware configuration, which can fix any errors caused by a corrupted CMOS chip.

cmos battery located

How to Reset CMOS

To reset the CMOS chip, you will need to follow these steps:

Step 1: Turn off your computer and unplug it from the power source.

Step 2: Open the computer case and locate the CMOS battery. It is usually a small silver disk-shaped battery located on the motherboard.

Step 3: Remove the battery by gently pushing down on the retaining clip and pulling it out of its socket.

Step 4: Wait for 10-15 minutes to ensure that all the data stored in the chip is cleared.

Step 5: Reinsert the battery back into its socket, making sure that it is inserted correctly.

Step 6: Close the computer case and plug in the power source.

Step 7: Turn on your computer and enter the BIOS setup utility by pressing the designated key during startup. The key may vary depending on the computer’s manufacturer, but it is usually F2, F10, or Del.

Step 8: Once in the BIOS setup utility, you will need to reconfigure the system’s hardware settings to your preferred configuration. This may include setting the date and time, selecting the boot device, and configuring the CPU and memory settings.


The CMOS technology is an essential component of modern electronic devices, allowing for faster, more efficient, and more reliable performance. If you experience issues with your computer’s hardware configuration, resetting the CMOS chip may be a useful troubleshooting step. However, it is important to note that resetting the CMOS chip will clear all the data stored in it, including the BIOS settings. Therefore, it is essential to backup your BIOS settings before resettingĀ  to avoid losing any critical configuration data.

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VM Staff

This content was written by the expert Velocity Micro staff.

1 thought on “What is CMOS and How to Reset”

  1. I had no idea that the CMOS had such an impact on my computer’s performance. It’s fascinating to learn how such a small component plays a crucial role. Great job on breaking it down for us!

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