That sounds like a used Radeon 9800 Pro I gotten in April, 2007. It would sometimes look fine and most of the time, far from fine, the majority of the time, even the BIOS screen was corrupted! It seems that reseating it solves it, but always comes back! Thus, it's looking like a possible common problem with Radeon 9800 Pros. Sorry. It may be a PCB issue! Because reseating it can temporarily solve it! But, don't even expect it to even go 1 hour before going back to video corruption. My Radeon 9800 Pro suddenly gave video corruption when all I was running was a hard disk drive utility! Warning, an alcohol cleaning probably won't change anything! I have a feeling that it's a common with Radeon 9800 Pros. Thus, I ended up getting an eVGA GeForce 7600 GS and it's still fine, AFAIK.