Clearing the CMOS can be done a few ways although there are thousands posted on the net so lets just talk the basics. The most common way is to use the jumper on the motherboard. This jumper has two settings. Normal and Clear. Moving the jumper to the Clear setting will erase the settings stored in CMOS. It does not remove the BIOS itself, only the user defined settings within the CMOS. When you clear the CMOS you will most likely see the error message “CMOS Checksum Error” on the next reboot. You can enter the BIOS setup at this point or before and reconfigure the settings.

Another method is to remove the CMOS battery from the system. Removing the battery is usually the second method as it may take anywhere from 15 minutes to 8 hours in order for the CMOS to loss the settings. Once the CMOS is clear, you should know by the “BIOS checksum error, press F1 to continue “, or “CMOS Checksum Error – Defaults Loaded” message at bootup. read more…