Robor, I've got one more thing you can try before you dump your Radeon. I got this from an nForce forum but it might work for you, too.
1. Uninstall all the ATI software. All of it. Don't reboot.
2. Run Driver Cleaner. Don't reboot.
3. Run Cab Cleaner. Reboot.
4. On boot, cancel hardware detection. Install the ATI drivers. Don't reboot.
5. Go into Services (Administrative Tools), provided you are using Win2K or WinXP, and set ATI SMART and ATI Hotkey
Poller to Disabled. Reboot.
6. Install ATI Control Panel. Don't reboot.
7. Go back into Services and set ATI SMART and ATI Hotkey Poller to Automatic. Reboot.
On the last reboot, the screen may flicker a bit while the ATI SMART service tries to determine the best configuration for your card. This is normal. At this point, every ATI card I have installed in my computer in the past 6 months has worked. As others have said, you might have to turn off Fast Writes. It's a hit and miss thing. It works for some and not others. But you will hardly miss it if you have to turn it off.
I hope this helps, your card ought be a great gamer for you. Good luck.