Radeon HD2400XT Stuck in VGA mode

Hi,

I have an ATI Radeon HD 2400XT, PCIe. Recently, it started doing something strange. When I installed Windows Vista on my PC, the display was stuck in 640x480x16color mode, and no matter what I did, it would stay there, even with the drivers installed.

Funny thing is, it did the same thing after installing XP, but once I had installed the drivers, it works perfectly.

Just for the hell of it, I tried to boot an Ubuntu LiveCD, and it would go through the boot process, but once it got to the point where it was time to enable graphical mode, the screen just goes black. It didn't turn off or go to standby.. just receiving a black signal.

Anyone have any idea how to fix this? I would like to not be stuck with XP, and buying a new video card is at least a few months away.

Thanks