Last time I saw this, it required a reinstall of the OS. It's also possible you have a failing hard drive. Start with the format and reinstall, if that fails, get a new hard drive.
Everything boots O.K. but after the OS select screen (theres only one option, Windows XP pro) it just goes blank. I tried in safe mode and it freezes right after it loads the GDI32.dll. It just, kinda, stops. All the fans and water pump is still going, even the graphic card fan. The HDD is spinning. If i just leave it with hopes to unfreeze, it doesn't. It's just always stuck. Help, Please.