Q&A: Replacing the Motherboard Battery - NYTimes.com

Q.

My ThinkPad laptop asks me to reset the date and time each time I boot up. Why?

A.

Although there could be software issues involved, the battery on the motherboard may be weak or dead. This battery ? sometimes referred to as the backup battery, BIOS battery or CMOS (complementary metal oxide semiconductor) battery ? supplies power for the computer to retain basic settings like time and date.

Replacing the CMOS battery may fix the issue. If you do not feel like paying a computer-repair shop, you can do it yourself. You need to buy the correct replacement battery (less than $10). Open up the laptop?s case so you can swap in the new power cell. Lenovo?s support site has online manuals for most ThinkPad models that show the location of the CMOS battery. Third-party repair sites like iFixit offer illustrated guides for some laptops as well.

Source: http://gadgetwise.blogs.nytimes.com/2013/02/13/qa-replacing-the-motherboard-battery/

robyn