Please list your components. Something is probably being stressed, but we can't tell what without that list. Is the shutdown immediate, within seconds or minutes, and does it matter if the PC has been off for a while?
when windows xp starts loading. Heres my components:
Asus M4A77TD MOBO
Phenom II X3 740 (Ocd' 3800)
G-Skill Ripjaws PC3-12800 (1600 MHZ)
ATI Radeon 4670 ( 1GB DDR3 )
OCZ Stealth X Stream 700 W PSU
Zalman 9700 110mm CPU heatsink fan w/heat pipes. (Runs around 50 c when load for a couple hours)
At windows loading I'd say either core voltage or the RAM is OCed too high, which I've commonly noticed causes a crash after POST but it could be either... try raising you RAM timings by 1, or try selecting a slower speed just to see if it boots then. If it does, you know where the problem lies and if it still has the same issue, then it's likely something with the CPU OC although it might potentially be something else. Hopefully an AMD expert can give you some better advice than me.
yeah, when I tried to raise the bus the first thing I did was drop my NB to stock and maded sure the mem was ok. I think its the ram I have because my mobo doesnt support 1600 unless its 1066 or 1333 ocd'. The ram I have is 1600 mhz so thats probably the problem. I tried downclocking to 1333 and then raising the bus and HT and NB all at once and no luck either. If I have my own selections open in bios they all adjust with each other ( I.E. BUS, HT LINK, NB)