CMOS Checksum Error

Solutions

Drivers

Others

CMOS Checksum Error Solution

After a few months use, one of my system started displaying "CMOS checksum error" message every time the computer is booted. I immidiately undestood that there is a problem with CMOS Battery. This problem is very common in older computers and very annoying one too. Here is the solution for this problem.

Every computer will have a small lithium battery on its motherboard which keeps on supplying power to the PC's RTC (real time clock) and system BIOS even when you turnoff your PC.

When this battery fails ( after its life time ), The system will not be able to hold on to BIOS settings which are required every time you start the computer. Hence the PC starts showing "CMOS checksum error" message at the time of booting.

Solving this problem is easy. Here are the steps to follow.

• Turn off PC. Disconnect all power cables. and open PC cabinet.
• On the mother board locate the lithium battery cell holder.
• Gently press the battery holder to release the battery from its place (observe which face is the top and which is bottom).
• Now observe the face of battery, it should have a model num on it.
• Usually CR2032 is the battery num to use but see and confirm yours.
• Get a new battery from electronics shop with the same model num.
• Insert it carefully into the battery holder on motherboard.
• The battery position should be as it was in the earlier battery ( Otherwise the battery may explode ).
• Make sure that the new battery is firmly sitting on its holder.
• Reconnect all cables and turn on the PC.
• Set once all your default BIOS settings and save and exit them.
• The problem should be solved now.