“CMOS checksum Error: Defaults loaded”…

When you power up your computer and the screen displays the above error message:

What causes this error?

A checksum error shows that boot up settings which were previously set have been changed. This usually happens when the battery looses its charge and thus fail to retain the CMOS settings. This can also be caused by a power surge and a damaged motherboard.

* Bad CMOS memory chip. This does happen. It’s a small, couple K battery backed chip. The chip itself, mainboard tracings or circuitry leading to it could go bad or be defective.

* Mainboard is shorting on the case somewhere. The tracings on the mainboard can definately short/ground or have periodic shorts causing the cmos memory to become corrupt.

* Something electromagnetic is effecting the CMOS memory. A poorly shielded fan or other magnetic source is wiping out the CMOS memory periodically. You don’t have like a refridgerator magnet on the side of the case do you?

* Temperature. If for some reason your mainboard has a hot-spot, excessive temperatures for the CMOS chip can cause it’s contents to scramble.

* Unstable power. If one of your voltage rails from the PSU is bad, it can wipe CMOS memory contents. Get a hardware monitor and let it run to watch voltage ranges.

* BIOS virus. Some virii attack the BIOS/CMOS memory space. Run a full scan and if you cannot afford a good virus program, try AVG. Even if your system comes up clean, look for patterns in usage (like a particular CD you use when it happens, etc.etc.)

Common Solutions to clear this error:

Restart the computer, If the error persist, replace the CMOS battery
Enter the values back into CMOS or reset values to default