CMOS Error

I am putting together a new machine with a Biostar M7VIG Pro 400 board and a Sempron 2400 CPU. I had a PowerColor Radeon 9550 I was trying to install as well. Every time I tried to install with the card in XP would crash when trying to format the drive. I took the card out and installed everything with the onboard Sis card. Afterinstalling, I stuck the card in and installed the driver. It seemed to work, but then it started re-booting. I updated to the latest driver, but that did not help. I took out the card, but now the onboard card is not working either. I put in a Nvidia card from another PC, but it was the same. It goes through the boot sequence, but just before it asks to boot from CD drive, the screen goes blank. I went into the BIOS and restored the defaults, but that didn’t seem to fix the problem. I put the new card in my other box, but it did the same blank screen. If I reset the CMOS, when it boots I get this message:

“CMOS Checksum Error - Defaults Loaded
Warning! System had reset due to overclock setting
Please re-enter CPU settings in the CMOS and remember to save before quitting”

Long story short, Does anyone know how to clear this up? I read on google it may be a battery error. I may get a new one if can’t come with any new ideas. Thanks for reading. Any help greatly appreciated.

Go into BIOS and select load default settings, change the CPU setting and then save and quit.
btw, your mainboard is not using a SiS-chipset, it’s VIA KM266.

Thanks for the reply. I don’t know how I got Sis into my head. I did try that already thanks.