CMOS Checksum Error Defaults loaded appears when something goes bad with the BIOS when you start the computer. Read this article to find the fix.

Fix The CMOS checksum is invalid, The CMOS will reset to the default configuration, and the computer will restart CMOS, Reset (502) on HP PC.

If you're getting errors when you boot your PC, the problem may be nothing more than a dead CMOS battery. Fortunately, they're cheap and easy to replace--on desktops, anyway.

CMOS checksum error, computer beeps during bootup ijohnson Published June 28, 2006 ...