HEMISENT, I'm in exactly the same boat (no pun intended) as you and Moog. My Radeon 9700 Pro did exactly the same thing 2 weeks ago. I tried everything to fix it from checking and cleaning for dust to updating motherboard drivers etc.
Nothing worked so in the end I had to buy a new graphics card (X850 Pro). I was lucky enough to buy it 2nd hand from a squadron mate but it had never been used.
I'd suggest buying the X1950 Pro 512MB (if you're after a superfast AGP card), they're available relatively cheaply considering how fast they are. I've seen 1 for £150 (about $275 US) which is cheap here.
Good luck in whichever route you decide to take.