p4S533/1.8A problems

I had a the following

p4 1.8a
asus p4s533
samsung pc2700 512 MB original
radeon 8500 retail

i was able to run it at 2.61 at 1.55V...it ran fine tested with 40 cycles of 3dmark2001 and a few hours of quake3...
used it for a couple of days...
then my new case arrived and i transfer it...it started to boot in windows xp sporadicly and the mic didn't work...the sound card was fine..but not the mic...

i rma the MB and got a new one...now it booted fine into windows everytime...but i can't even run 3dmark2001 at 1.8..stock speed... it just froze every time...

is this an issue with driver? MB? cpu?

i installed the sis ide driver...sis agp driver...latest catalist video driver..

????

It ran with my old asus geforce2 32MB graphic card but with my radeon 8500 it froze.... argggggggggg

the first p4s533 ran with my radeon 8500 fine as i sadi above...but now it won't!!!!

i had problems with the sis ide driver.. try uninstalling it