Short for Complementary Metal-Oxide-Semiconductor, CMOS is a small portion of memory whose function is to store your PC’s BIOS or UEFI settings.
There is an array of reasons based on which you might need to reset your CMOS; you might be experiencing troubleshooting or hardware compatibility issues, maybe your PC’s doesn’t boot properly, or it hangs a lot.
Being in a similar situation to the aforementioned ones, resetting your CMOS can set things right.
How to Reset Your CMOS
In this guide, we will get you up to speed with all the methods that you can follow to reset your CMOS. So, let’s begin!
The simplest way of clearing your CMOS is to head to your BIOS/UEFI setup utility and perform a factory data reset.
For that, first, restart your PC. As soon as the first screen with your computer manufacturer’s name pops up, press the relevant key to navigate to the BIOS/UEFI menu. Depending upon your manufacturer, this key can be either of the following: Esc, Del, F2, F8, or F12.
Anyway, once you’re in, look for the phrase similar to any one of these; reset to factory default, load setup defaults, load BIOS defaults etc.
After selecting the reset option, save the settings and reboot your PC.
In this method, you will be looking for a small button labeled ‘Clear’ or ‘Reset’ on your case that can be used to reset the CMOS.
So, first things first, turn off your computer and plug it off from the power outlet. Now, search over the body of your CPU for a button labeled ‘Clear’ or ‘Reset’.
You will most likely find it near the power button. Once you do, press it for 5-10 seconds and then, power on your PC.
Tap the right key to navigate to your BIOS options when prompted.
Finally, make the desired modifications in the BIOS setting and reboot your computer.
(Note: If your motherboard has the option ‘optimized defaults’ for the BIOS options, choosing it is highly recommended for beginners.)
This method commonly applies to the top-notch motherboards out there. It involves opening up your CPU and locating a tiny button labeled commonly as “CLR,” “CLEAR” or “RESET” on your motherboard.
Firstly, turn off your CPU and press the power button multiple times to ensure all the motherboard’s capacitors are completely discharged.
Next, unplug your computer power outlet and open up your CPU’s case.
Locate the button mentioned above. If you face trouble finding it, refer to the motherboard’s manual.
Once you’ve found it, press and hold it for 5 to 10 seconds using either your finger or a pencil. If you do it with your finger, be very careful do not forget to ground yourself beforehand.
Having done that, reconnect your PC to the power socket and turn it on. Head to the BIOS setting, make the right adjustments and you are good to go.
4. Adjust the Motherboard Jumper
Applicable to mostly the desktop computers, this way of resetting CMOS demands you to adjust the right jumper on your motherboard.
So, firstly, power off the computer and press the power button multiple times to clear out any capacitors. Then, unplug the power outlet.
Now, open your computer case and look for the CMOS clearing pins on the motherboard. These pins are usually in a series of two or three and are labeled as “CLEAR,” “RESET”, “CLRCMOS” or “CLRPWD”.
Image source: HP
If it is a two-pin configuration, remove the plastic jumper; if it is a three-pin configuration, move the jumper from the default 1-2 position to 2-3 position.
Wait out for 1-5 minutes before putting the jumper back to its original position.
Lastly, restart your PC. (Depending on your motherboard version, you might need to enter BIOS and perform a factory reset before you can begin using your computer.)
5. Replace the CMOS Battery
In this method, you will be removing the CMOS battery from your motherboard, resulting in the erasure of all data in it and then, replacing the battery. This is because this battery allows CMOS memory to keep running even when your PC is off.
To avoid any harm to your CMOS battery, only resort to this method when none of the other methods works for you.
Power off your computer and press the power button multiple times to discharge all the motherboard’s capacitors. For laptops and tablets, take off the main battery.
Now, disconnect your computer from the power outlet, open up the body of your CPU and search for the CMOS battery on your PC’s motherboard whereas for laptops and tablets, open the CMOS battery panel.
The CMOS battery is generally a coin-shaped, CR2032 battery fixed near PCI Express slots. If you still can’t find it, you can always look it up on your motherboard’s manual.
After finding it, remove it gently from its slot. You might find it position into place by a metal chip; if that is the case, take note of the orientation of + and – on the battery and try to cautiously slide out the battery without bending the chip.
If the battery is in connection with an onboard header via a wire as shown below, unplug the wire from the onboard header and then, remove the battery.
Once the CMOS battery is removed, wait for several minutes before placing it back. Finally, reboot the computer to finish up the process.
As far as the laptops and tablets are concerned, the CMOS battery is connected to the motherboard via a 2-pin connector. Unplug this white connector for the motherboard and plug it back on after 1-5 minutes.
All in all, there are a variety of ways to reset your CMOS. However, always first try to adopt the reset process through BIOS or UEFI Menu and if it doesn’t work out for you, move on to the other methods.
One of them will surely get the job done.