Can CMOS Battery Cause Computer Not Start? (Explained)

The CMOS can alternatively be cited as RTC (real-time clock), NVRAM (non-volatile RAM), or the CMOS RAM, which identifies as a complementary metal-oxide semiconductor, is an onboard, battery-powered semiconductor chip found inside computers that stores information. The information stored could range from the system time and date to system hardware settings for your computer.

The CMOS responsibility is to store the BIOS setting of your laptop responsible for storing information needed to run your computer hardware for easy detection and adherence to instructions. The CMOS functions do not affect the functionality of your computer. At the same time, it is essential to note that CMOS can affect your computer from starting and might not affect your computer in another way. 

Can CMOS Battery Cause Computer Not Start?

The CMOS (complementary metal-oxide semiconductor) is fully a computer motherboard component, and its crucial role is to store data about your computer BIOS (basic input/output system). This chip can store data on whether the computer is ON or powered OFF. If a case where the chip fails, the data stored will be lost, and this will affect your computer startup function. Therefore the CMOS battery can cause your computer not to start.

While it is also important to note that when the chip starts to leak, it’s a sign that the CMOS battery is about to fail, this issue could be fixed by replacing the CMOS battery, and in the worst scenario, it may require replacing the entire motherboard.

cmos battery

What Causes A Dead CMOS Battery?

The CMOS battery is usually built to last 2-10 years, depending on how the laptop is used; when there is fair usage, the CMOS battery lasts longer. The death of the CMOS battery is often caused by the corruption of the CMOS, which is responsible for loading the data from the storage device to the primary memory.

When there is an interruption during the BIOS update, the system will send a prompt message indicating BIOS corruption has been detected. And this signaled the beginning of a corrupted CMOS, an unprecedented CMOS battery death. 

How To Detect A CMOS Battery Failure?

The CMOS acts as a battery-powered semiconductor chip found in your laptops and pcs, and it helps the computer store important information needed for startup. The CMOS battery failure is best detected by:

CMOS Battery Failure Symptoms
  • When the operating system of your computer fails to boot.
  • The computer shuts down coincidentally without the users’ input.
  • When your computer constantly shows error messages such as booting error and your computer’s inability to detect the disk drive. 
  • Continual beeping and the wrong time and date prevent your computer from connecting to the internet.  
  • Another factor to note is CMOS read error, CMOS checksum error, and CMOS battery failure. 

The above-listed factors could indicate earlier detection of CMOS battery failure. 

How To Replace The CMOS Battery?

Having ascertained the need to replace the CMOS battery on your computer, it is essential to understand these basic steps whenever you want to replace it.

  • Unplug all the connected cables to the computer.
  • Then unplug the power cable to the computer and shut it down by holding the power button before removing the battery.
  • To access the laptop panel, remove all the screws from the rear end of your laptop and slide the panel off.
  • Locate the CMOS battery and note the direction of the battery for easy replacement and then remove the battery
  • Install the new recommended battery in the socket where the old battery was removed, taking note of the direction of the battery.
  • Place the panel back and screw the secure rear panel, connect all the removed cables, and turn on the PC. 
  • After booting, the time and date must have been corrected, and your laptop must be ready for use. 

Does CMOS Battery Affect Computer?

The eventual expiration of the CMOS after a long period of using your laptop will affect the function of your computer. Since the CMOS holds vital data needed for your computer to boot up, the computer’s ability to boot will be affected when the CMOS battery is down.

The battery failure will cause the computer to give the wrong time and date, while it is also important to note that some computers are not affected by the CMOS battery failure. But the CMOS memory holds various data configurations and other settings needed for your computer hardware and software startup.

Can A Dead CMOS Battery Stop A Computer From Booting?

Your computer will begin to malfunction when the CMOS battery loses its energy and durability, which in turn affects your computer’s BIOS startup data. A dead CMOS battery does not stop your computer from booting. Instead, it will affect the time and date settings on your laptop.

Another noticeable thing is that your computer will have to boot with default BIOS settings or be prompted to choose the drive on which the operating system is installed each time you launch your computer. 

Can CMOS Battery Cause Blue Screen?

The CMOS battery failure on your computer doesn’t cause a blue screen, except in cases where your computer drives stop working. In cases where the CMOS pop-up CMOS checksum and read errors, it will trigger the driver’s blue screen and crashes when the driver stops working.

But the problem associated with a dead CMOS battery is the wrong time and date setting, frequent boot errors, and failed internet connection due to the wrong time and date. 

Can A Dead CMOS Battery Cause No Display?

Generally, a dead CMOS does not cause a no-display screen on your computer, even when the battery is inert. The well-known issue with a dead CMOS battery is the display of checksum error messages, incorrect date and time, and failed internet connection due to wrong date and time.

What Problems Can A Bad CMOS Battery Cause?

The CMOS dead battery is not associated with any severe damage to the computer, but it can affect some of the primary functions of your computer. A bad CMOS battery will cause your computer to display inaccurate information about the time and date on the computer. It also affects the peripheral function of your computer, showing a checksum error and network or internet connection issues accompanied by beeping sounds from the computer motherboard. 

What Happens If I Don’t Replace CMOS Battery?

Indeed, nothing will emerge if you refuse to replace the old dead battery of your computer CMOS. Your computer will show an incorrect or slow system time and date, loss of BIOS setting, and unresponsive hard drives and peripherals. Other than the apparent signs that accompanied a dead CMOS battery, it is encouraging to get a new CMOS battery to replace the old and dead battery. 

Does CMOS Battery Damage Motherboard?

The motherboard of your computer is not damaged or affected as a result of a dead CMOS dead battery; it only affects some primary functions of your computer, such as the time and date setting of your computer, causing the peripheral device to be unresponsive and loss of connection to the internet.

It should be noted that removing the old dead battery and replacing it with a new one will affect your computer’s BIOS setup, such as the boot sequence and overclocked computer components, returning it to default settings. 

Can I Change The CMOS Battery Without Losing Settings?

The CMOS battery can be changed without losing your BIOS settings, provided there is a quick change of the battery while the computer is still on. This is done by sliding a piece of paper underneath to catch it in case of the battery drops, although this method is not recommended. Another way to ensure the safety of your data is backing up to a drive before removing the CMOS battery to be safer. 


Is It Safe To Reset CMOS Battery?

Resetting or removing the CMOS battery on your computer can cause the BIOS setting to reset to the default setting. The CMOS battery stores persistent memory for the BIOS setting, which includes the date and time setting, location setting, and overclocked procedure for your computer.

Carrying out a reset should only be done when there is a reason, such as troubleshooting your computer problem or clearing a forgotten BIOS password. If all these reasons are absent, there should be no reason to reset your CMOS battery. 

What Destroys CMOS Battery?

The CMOS battery is designed to last between 2-5 years or more, depending on the usage of the computer. The rate at which the CMOS battery drains is slow but constant each time the computer is put to use, and an increased temperature during use is also a contributing factor to what destroys the CMOS battery.

The CMOS battery drain is always at zero whenever the computer is used; the more the computer is used, the CMOS battery load decreases.


It is a fact that the CMOS battery is responsible for keeping the CMOS and BIOS powered on while your computer is not plugged into a power supply. It helps keep track of the date and time on your computer while keeping the data configuration and system settings needed for your computer to boot. The CMOS battery failure has a clear and noticeable indicator that any computer user to be aware of to prevent unnecessary damage to their computer.

When your computer displays the wrong time and date and has a booting problem, it clearly shows that your CMOS battery is completely depleted and needs replacement. And as complicated as replacing the battery may sound, it is straightforward when you want to replace it.

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