I bought an ATI Radeon X300 LE 256 meg card that is PCI-express x16, which is what my computer is supposedly compatible with, and I upgraded my power supply to 400 watts, 50 above what is recommended for this video card, and it won't work at all.. I'm thinking that this card might not be compatible with this version of the PCI-Express chipset or whatever, but I can't find out anywhere what card would be compatible with it...