How can I check if the CMOS battery is the culprit?

To check the CMOS battery, you'll need to access the BIOS settings. Restart your computer and repeatedly press the designated key (usually F2, F12, or Del) to enter the BIOS setup. Look for the CMOS battery information. If the battery is old or failing, it will likely indicate a problem. You can also visually inspect the battery for physical damage.