CMOS checksum error

[Cainxinth]

My MSI K7 Master had a bug that I thought I resolved by correcting the 3.3v pot on my PSU. However, I recently reformatted and the problem has resurfaced even though the 3.3v rail is at the proper level. I needed to boot to the cd-rom to install win2000, but every time I tried to enter the BIOS the computer would halt at a blinking cursor. So I flashed the CMOS with its jumper and I got in and changed my boot order. But, now every time I boot up I get a ?CMOS checksum error.? Hitting F1 lets the computer go ahead and boot into windows. I?ve read that this is standard after flashing the CMOS and all I need to do is enter and update the BIOS. But, the halt problem is preventing me again, and flashing the CMOS again didn?t do anything. I?ve tried flashing the BIOS off a boot disk to no effect. Any ideas? Thanks for you help.