GTX 260 crashing

heyy i recently just installed windows 7 64bit and unless i ram my GPU fann all the way too 100% with riva tuner my screen statrs flashing on and off, the screen gets all garbled, then i get the blue screen of death. but the annoying thing is even with the fan on high it does it too if im on the normal desktop for a long period of time (like if im web browsing or on msn/skype) I know its not my mother board or the OS cos ive installed a different version of the windows 7 64 bit on the same machine and it still happens. i also have tried it without the graphics card and guess what it didnt crash. what should i do? should i get the 32 bit instead or is there a way i can fix it without having too download win7 again. my specs are:

intel 3.06GHz duo processor
4 GB DDR2 Ram
ASUS Pro Turbo MOBO
950 Watt power supply
and the said XFX GTX 260 896MB

please help im sick of this darn thing crshing

around 60c =s