OK, bought a new Radeon 9250 PCI video card to install on my Dell Optiplex GX280 that had previously run on integrated AGP. Installed and I get a black screen upon rebooting except for 2 white pixels at the very top of my display. Switched back to AGP and installed drivers then repeated process and still black screen. BIOS is set to AUTO so it should be picking up the the card. Recognized it as a driver but no picture. Any suggestions?