New graphics card display problem

Hello,
I have a system built and running fine on a 4870, the card stopped working, so I put in my old 2600 XT. I've tried a couple of different drivers, but it keeps seizing up, the screen freezes and unfreezesd randomly every 10 - 15 seconds. It runs beautifully in safe mode, so I'm pretty sure it's a driver problem, I have tried updating the drivers, nothing seems to fix it.

Win7 64bit
9950
2600 XT
4GB ram
1Tb seagate HDD
 
K, did a sweep, deleted everything that seemed out of place. Listed Nvidia drivers when I've never had an Nvidia card in this machine.<G> Anyhow, no help. Runs fine in Safe mode, crashes in regular. Since installing this card the whole computer is acting funny though.
 
K, Installed Win XP Pro X64 on a hard drive partition that I had empty, same results except that it won't even display with the ati drivers, will run on the windows generic, and will run in safe mode, just poorly, but better than no video at all.