Failing Video Card (?)

Hey folks, thanks in advance for the help. I've searched through the forums, but haven't found anything related . . .

I built up my computer about 3 years ago. Specs:
Motherboard: Abit NF8
CPU: AMD Athlon 64 2800+
Video Card: XFX GeForce 6800
Other stuff . . .

Anyhow, it's been working fine for the last 3 years, running XP, until one day I had the computer hibernating overnight, powered it on in the morning, and the screen was all buggy with video artifacts, the screens flashed on and off, gave a quick blue screen, and then the computer restarted. The closest example I could find of the artifacts is at http://www.playtool.com/pages/arti [...] emory3.gif

Anyhow, I couldn't get it to go away. I assumed it was some sort of virus, and it'd been a while since I reformatted XP, so I formatted the partition and reinstalled XP. I then made a 3rd partition and loaded Ubuntu 8.04. In XP, I loaded the appropriate drivers from the CDs that came with the hardware, and everything ran swimmingly. Then, in Linux, I changed the Display driver from the generic linux driver to the nvidia drivers. A couple days later, while in XP, the screen went nuts again with artifacts. I thought "oh well" and restarted into Ubuntu - same problem.

I can boot into Safe Mode in XP without problems. I can also use Ubuntu as long as I revert to the generic video drivers. I've tried updating the XP drivers with the latest version of the video drivers from the XFX website, but no help. I also tried slowing the AGP port to 4x, and also no help.

It would seem to me that, if it were a hardware failure, it would give problems regardless of safe mode, drivers, etc. And the boot screens/images are always perfect, too, which would indicate a software problem. But I don't know what else to do!

Anyone have any thoughts? Thanks again!
Nick

Thanks . . . I downloaded nibitor and tried running in Safe Mode (because that's the only way I can access XP). When I try to "Select Device" in the program, it gives me an error: "Cant start driver: 1084" Any suggestions?

Thanks!