Will Motherboard Boot Without CMOS Battery?

The CMOS battery is a small device that provides power to the motherboard. If this battery doesn’t function properly, the PC will not be able to start.

If you work in a computer repair shop and see a user with a motherboard that won’t boot, do you think you might get lucky? What would happen if the motherboard didn’t have a CMOS battery? Read on to find out!

Will Motherboard Boot Without CMOS Battery?

If your motherboard does not have a battery, it will not boot. If your computer was recently turned off and then back on, the motherboard may have needed time to initialize and could not find the appropriate service or drivers.

Try pressing F2 during POST to get into the BIOS, disable any onboard devices you don’t need (like USB ports), change the default boot order in the BIOS to CD/DVD first, and then try rebooting. If that doesn’t work, contact your motherboard manufacturer for assistance.

Why Rely on a CMOS Battery

A CMOS battery is a small but important part of most computer systems. It stores critical system data and helps the motherboard boot up properly. If your motherboard doesn’t have a CMOS battery, you might not be able to start your computer.

Without a CMOS battery, your computer won’t be able to start. The motherboard will attempt to boot from its internal storage, but without the proper system data, it won’t be able to do much else. In some cases, this can permanently damage your computer’s components.

If you’re ever in doubt about whether or not your motherboard has a CMOS battery, check the manual that came with your computer or search online for instructions on how to replace it.

How to Remove and Insert a CMOS Battery

If your motherboard fails to boot or power up using the default settings, you may need to replace the CMOS battery. There are a few ways to remove and insert a CMOS battery on different motherboards.

See also  What Is A Computer’s Motherboard?

The battery is accessible through the motherboard cover (or tray). On others, it’s hidden behind the motherboard. Follow these steps to access and replace your CMOS battery:

  1. Remove the cover or tray if necessary. On some models, screws hold it in place.
  2. Locate and remove the CMOS battery. It will be either an 8-cell or 6-cell unit with a silver label.
  3. Replace the CMOS battery by popping it into place and screwing it with the provided screws.

What is the CMOS Battery, and When Should You Change It?

The CMOS battery charges the motherboard’s RAM, allows it to start from a cold boot, and stores other settings, like the time and date. If your computer won’t start or you notice that the time and date are incorrect, then it’s likely that your CMOS battery is dead.

To replace your CMOS battery: Unplug all cables from the computer Check for the user manual nearby for the disconnection sequence. Proceed with the following steps

  1. Remove two screws securing the keyboard cover
  2. Lift off the keyboard cover
  3. Locate the CMOS battery
  4. Replace the CMOS battery by gently pressing down on the battery until it snaps into place.

Replacing your motherboard’s CMOS battery can help troubleshoot startup and system functionality. Additionally, if you forget to charge your motherboard’s CMOS battery before you use it for the first time, you may experience problems with the computer starting up correctly.

Tips on keeping your CMOS battery in good shape

Like most people, you don’t think about your CMOS battery much. But if your PC won’t start up or you can’t get it to turn on, there’s a good chance the battery is at fault. Here are a few tips on keeping your CMOS battery in good shape:

1. Keep the battery clean: It will not work if it gets dirty. Clean the battery with a mild soap and water solution every couple of months or when it shows signs of wear.

2. Avoid overcharging: Overcharging can damage the battery and reduce its lifespan. Only charge the battery when it says to do so on the charger’s label.

See also  How To Change Cooler Master Fan Colour

3. Keep an eye on the voltage: Ensure your charger’s voltage reading stays between 4.2 and 5 volts while charging your CMOS battery. A lower voltage means that the battery is overcharged and may be damaged.

Replacement parts for CMOS batteries

The motherboard is responsible for initializing and starting up the computer. Without a functioning motherboard, you may not be able to start your computer or even access important data.

One common issue with CMOS batteries is that they can lose power over time, causing the motherboard to fail to boot. You can try several replacement parts if your motherboard doesn’t start without a CMOS battery. 

If your computer won’t start at all, the first thing you should do is try resetting the system by pressing and holding both of the reset buttons on the keyboard for 10 seconds. You’ll need to replace the CMOS battery if that doesn’t work.

There are several options available depending on your computer type: MB/core2 duo/Pentium 4/i3/i5/i7, laptop, netbook, and desktop. 

The battery is likely located at the bottom of the machine near the AC adapter jack if you’re using a laptop. To replace it, first, remove any screws that hold down the casing around the LCD screen. Once it’s free, carefully lift off the LCD screen and set it aside.

Underneath is a removable battery cover. Pry it open with a thin object such as a screwdriver and remove the old battery. Replace it with a new one and replace all screws in place. You can also buy an aftermarket replacement battery if necessary. 

If you’re using a  desktop, the battery is likely located in the rear of the machine. To replace it, remove the motherboard cover by unscrewing five screws on each side.

Once it’s free, lift off the cover and locate the CMOS battery. It will be a small, rectangular battery with a white label. Remove it and replace it with a new one. Replace all screws in place and replace the motherboard cover. 

If you’re using a netbook or laptop, there’s a greater chance that the battery is dead and needs to be replaced completely. In most cases, this means removing the entire bottom of the machine.

See also  Does A PC Case Matter?

Several screws hold it down, and once they’re removed, you’ll be able to lift it off and access the battery. If your netbook doesn’t have a removable bottom, you’ll need to find an aftermarket replacement battery online or in stores. 

If your computer doesn’t start at all, be sure to check out our guide on how to reset your computer.

Frequently Asked Questions

How can I replace the CMOS battery in a motherboard?

To replace the CMOS battery, remove the cover from the back of your PC and locate the battery compartment. Carefully remove the old battery and install the new one. Make sure that it’s properly seated and push down firmly until it clicks into place. Reinstall the cover and turn on your PC. 

What are the risks of disabling or removing the CMOS battery?

There are some risks associated with disabling or removing your motherboard’s CMOS battery: 
1. You might lose data if you disable or remove your motherboard’s CMOS battery without first backup that data using an appropriate recovery tool. 
2. If you accidentally disable or remove your motherboard’s CMOS battery while Windows is running, you might be unable to fix that problem using traditional methods such as rebooting your PC and reinstalling the operating system. In that case, you might have to take your PC to a service center to have it fixed. 
3. If your motherboard has a built-in security feature that protects its CMOS memory against unauthorized access, disabling or removing the battery could disable or alter that protection, potentially rendering your motherboard inoperable.


Motherboard manufacturers are always looking to save power, so it’s no surprise they’re experimenting with a new way to boot a computer without needing a CMOS battery.

This means that if your computer goes bad and you can’t access the CMOS settings to switch out the battery, you may not be able to get your computer back up and running.

If you worry about this, check with your motherboard manufacturer to see if their computers will boot without a CMOS battery.

Share post on
Matt Wilson
By Matt Wilson

Matt Wilson is a PC gaming and hardware expert with years of experience. He's a trusted tech product reviewer for gamers and tech enthusiasts.

PCedged is reader-supported. When you buy through links on our site, we may earn an affiliate commission.

Knowledge Base

Tips to Lower Your Internet Bill

 Everyone needs a good home internet connection today. However, a good internet is anything...

By Matt Wilson
How To Add More SATA Ports To Your Motherboard? Knowledge Base

How To Add More SATA Ports To Your Motherboard?

SATA, which is short for Serial Advanced Technology Attachment, is the current industry standard...

By Matt Wilson
Test Motherboards Without A CPU Knowledge Base

Test Motherboards Without A CPU

The motherboard is one of the most important components in any computer. It connects...

By Matt Wilson
Can PCI-E X4 Card Fit In X16 Slot? Knowledge Base

Can PCI-E X4 Card Fit In X16 Slot?

There are many questions that a PC builder may be asking when trying to...

By Matt Wilson
How To Buy Used Graphics Cards? Find Out the Solution Knowledge Base

How To Buy Used Graphics Cards? Find Out the Solution

Recently, I was looking to purchase a graphics card for my PC but needed...

By Matt Wilson
How To Test RGB Fans Without Motherboard Knowledge Base

How To Test RGB Fans Without Motherboard

RGB fans are the latest trend in computer hardware. They have a fan blade...

By Matt Wilson
Upgrade Your Minecraft Experience with These Powerful Graphics Cards! Knowledge Base

Upgrade Your Minecraft Experience with These Powerful Graphics Cards!

Minecraft is one of the most popular video games of all time for a...

By Matt Wilson
What Is a Discrete Graphics Card and Why Do You Need One? Knowledge Base

What Is a Discrete Graphics Card and Why Do You Need One?

A discrete graphics card is a specialized hardware designed for gaming and other high-performance...

By Matt Wilson