My computer began stating that its 6600GT AGP was not getting supplemental power. I checked the molex plug and tried another one that was supplying power to the DVD drive. It did not help. I swapped video cards with a known good one. I received the same message on booting up. I swapped power supplies with a known good one. Same warning on both cards. Then I began getting overclocking error failures at post, except I don't overclock. Now the system refuses to boot at all with any card in the AGP slot. It posts and boots fine if I put in just an old PCI graphics card. If I add back the AGP card it won't even post, no matter whether the BIOS looks to PCI or AGP graphics cards first. Bottom line: For some reason I can no longer boot this cpu with an AGP card in it. I do not tweak this system in any way, and have not changed any settings since building it about a year ago. Any thoughts? Thanks for any ideas.