quick note - I had vista 64 installed with a Sapphire 4850 and the latest drivers (9.**), it continued to give me BSoD, I'm fortunate enough to be a college student with access to the every version of windows, so installed vista 32 and the recent drivers worked fine, so I went back to my vista64 and installed some older drivers (8.8) and they worked fine, the major difference between the new (9.**) and the old (8.8) is the CCC "overclocking" isn't present in the 8.8 drivers...
try and find the older drivers, that might work... (I had a disk, or I'd give you the link)
-jt