Hello everyone. A few weeks ago, we had a problem with our Dell Dimension 8400's graphics card showing a corrupted BIOS screen while booting up. So we replaced our old graphics card with an Asus EN9600GT Magic and attempted to start our computer. We are instantly confronted with a black screen and blinking underscore (before any BIOS screens) that remains indefinitely. Occasionally (two times) we have gotten a regular BIOS screen followed by the Windows XP loading screen and then a black screen with white mouse, but mostly the computer freezes on the blinking underscore. Is there anything we can do to regain normal functionality or is this a hardware problem? Thanks in advance, Michael.