After CPU swap, windows wont boot

Just like the title says, I upgraded from a 1.25 Ghz Amd Athlon (not sure of specific model) to a Amd Athlon 3000+. The motherboard which is a via kt600 does support this processor and the even faster 3200+, so compatibility isn't the problem. My memory is a 512 stick of kingston pc3200 ram which is rated at 400mhz which is faster than the 333 mhz front side bus of the cpu. So again, that shouldn't be the problem. The bios seems to recognize the 3000+ after i manually set the speed of 166x13. When the computer is first powered on it says Amd Athlon 3000+ at 2166 mhz.

Also, after seeing that windows would not boot with the new processor, i swapped the old one back in to find that windows would not boot with that one any longer as well. Is there some sort of setting that I could have messed up in the bios, or is my installation of windows going bad.

I have also already tried to do a repair install of windows, but I always get the blue screen of death when setup is loading the files.

I would greatly appreciate any help as that computer is completely useless at the moment.

Make sure you know how your BIOS was setup before clearing it though since you'll lose everyting.