CMOS (complementary metal-oxide-semiconductor) battery is a small, coin-shaped battery that provides power to the computer’s CMOS chip. The CMOS chip stores the computer’s BIOS (basic input/output system) settings, such as the time, date, and hardware configuration. If the CMOS battery dies, the BIOS settings will be lost and the computer may not be able to boot up.
Replacing the CMOS battery is a relatively simple process. However, it is important to take precautions to avoid damaging the computer. Before you begin, you should power down the computer and unplug it from the power outlet. You should also ground yourself by touching a metal object, such as a doorknob or water faucet.
