CMOS Checksum error???? Heeeeeeeeeelp!

[(RIP) willstatt]

Last night my PC gave the following message:

CMOS Checksum error.... Defaults loaded.

F1 to continue Del to enter Setup

I pressed F1 and all seemed fine apart from a message saying the date AVG virus database was incorrect and the clock a date were zero'd

I reset the time and date and all else functioned seemingly perfectly.

Turned it on tonight and got same message page.

So you boffins, what's the matter with the bloody thing?

Any help much appreciated.

Will

 

[cookie]

motherboard battery is shagged.

 

[(RIP) willstatt]

?

Is it a simple replacement job then?

Will

 

[shugie]

Is it a simple replacement job then?

Will

Can be, look for large round silver thing on motherboard, or consult manuel.

What motherboard is it?

 

[hommes]

Let me explain what has happened to your PC (probably).
There is a small amount of non volatile memory on a motherboard that stores the basic input / output system (Bios). This memory holds basic information the PC needs to boot up such as time and date, connected devices (hard drives, CD ROMs, etc) and lots of other stuff.
The Bios memory uses a 3 volt battery (CR2032) to run the clock and maintain the other Bios settings when the mains power is turned off. Nearly all Motherboards less than 8 years old use a CR2032 (or equivalent) battery. It looks like a large watch battery and is clearly visible somewhere on the board.
When this battery runs flat (usually around 3 to 7 years, depending on usage) your PC looses all the time, date and bios info when it is turned off. Next time you turn your PC on it looks for the info and finds none. It then tells you there is a checksum error. You can then hit F1 to load the Bios default values( sets the bios to the time, date and settings of the time it was first coded) or Delete to manually reset everything.
If you keep loading the defaults then the PC time and date will always be wrong. That’s why AVG thinks the database is out of date.
Until you replace the CMOS battery you will get this message every time you start your PC.

Hope this helps.