Now here's what I've found: I can connect the 24 pin ATX power cable and the entire computer will turn on: the fans and everything else is running, all except for the CPU which isn't receiving power and the graphics card doesn't spin up. As soon as I plug the 8 pin ATX 12v cable that's supposed to power the CPU, the computer will no longer turn on. It'll turn on for a milisecond and instantly turn itself off. I am using - antec 900 fsp everest 800w psu p5n-t deluxe mb q6600 go true 120 cooler 4 gb xms 2 corsair 800 320 gb seagate sata ii HD bfg gtx 275 oc so what could be the problem guys? Grounding issue?psu? Dead mobo or CPU? What's the minimum you need for it to power up, for example would it power on without the graphics card in place? It someones old system that I have bought so I know all the components have worked together.