Here is a doc with the steps to replace.
The CMOS battery is basically a watch battery - should last a few years. You don't lose anything - you should only have to reset the time. If you change it every two years, then you avoid the minor headache of a startup message stating that the time and date is incorrect. I usually wait until this message starts appearing, then remove the battery (with the power cord disconnected) and I take it to the local department store and buy another of the exact same type.
Please post rather than send me a message. It's good for the community and I might not be able to get back quickly. - Thank you.
06-01-2010 02:49 PM
I don't know if there is a common time frame for how long the batteries last in motherboards. I have never needed to replace the battery in any of my PCs and a couple of them are 5-10yrs old. Replacing the battery will cause the BIOS to go back to default settings, so it will lose any BIOS configurations you may have changed, but it won't delete any info from the hard drive, like your personal files and such.