same thing happened with my friends 9800 pro, he would have to do this weird thing with taking out the RAM and plug and unplug his card every time his computer booted up just so his card would work, or something like that. then he must've shocked it somewhere along the line, because now it acts as you're describing.
You should NOT of bought SAPHIRE. Same thing happened to me. Kept crashing, then glitching... I sent the Saphire (Radeon 9800) to ATI, and they sent me one built by ATI (nothing to do with Saphire) and no problems once so ever.