I've been trying to diagnose a Gateway LX6200. when you put in a video card that does not require power the video card works just fine. when you install a video card that requires it then its not seen. I've tried this with three different cards 6450/7850/7770. with the two 7xxx series cards I've been getting no amd graphics driver installed. but with the 6450 I get nothing. and the card is seen. is this something on the motherboard? I originally thought it was psu caused but this doesn't seem to be the case or am I wrong? Thanks in advance!!!