Are you able to try your card under XP via dual boot? I got the same issue (had two problems: I would get "Adapter has reset" under Vista, and would get a blue screen under Vista indicating a problem with "ATIKMDAG"). I did the same as you did; tried uninstalling the drivers using SkyMtl's procedure (ATI HD4870 & HD4850 Crossfire Performance Review) , and I had the exact same issue under a couple differnt versions of Catalyst.
From the research I did, it was blamed on drivers or overheating hardware. I have been running the same card now under XP for anout 3 weeks with absolutely no crashes, so I think my hardware is fine. I crashed 1-2 every couple of days under Vista, even after a Vista fresh reinstall like you. Weird I know, as I had an nVidia card that never had a problem for months under Vista and the computer worked really well. Would crash when folding very often (gpu at 100%), but has held up fine when folding as well under XP.
So I would try reinstalling the latest drivers using Sky's procedure I linked to above. Works for some people. I never got my problem fixed under Vista, but XP seems fine now. Otherwise, try stressing out your card by using a gpu folding client or using Atitool (ATITool - Overclocking utility for ATI and NVIDIA cards) to stress out your card to see if perhaps the hardware is wonky. I used XP to rule out hardware, as I assumed that my computer would crash in XP if there was a problem there.
Wish I had a slam dunk for ya...I never got my issue fixed under Vista so I'll be checking in here too...this is a common issue if you look around....if you can rule out hardware that might help though.
Well, I found a thread over at NCIX and it said to underclock the GPU. I did that, and now I can play FC2. I'm sure this isn't something to do with temps though, since before, I tried to run the game at 100% fan speed, but still it crashed. Would this be faulty hardware, and should I exchange it for another one?
why would i reinstall my audio drivers if i have graphical problems :S , anyways i already did that as i reupdated all my drivers today even the graphics card ones.. does not seem to have fixed anything. What would be the best way to underclock your card and how much would i underclock it