CMOS Battery Dying Out

Problem: After powering off the PC and switching it back on after a few hours, the time has changed.

Or the time always shows January 1, 2001. Even after rebooting, it shows the same.

Cause: The CMOS battery powers the real-time clock. This symptom indicates that the battery is dying. In rare cases, it could also mean there’s a problem with the battery port of the CMOS.

Solution: Replace the battery. If the symptom persists, there’s a good chance that the battery port is damaged. In this latter case, you may need to replace the motherboard.