Tried switching on with a screwdriver instead of the power switch and still have the same power cycling problem. The only thing's I've got in the case are the PSU, P5B Deluxe MoBo, CPU & RAM, no USB or firewire or anything connected.
I connected my system to the PSU in my old computer and it didn't have this cycling power problem.
Antec won't RMA, they told me I had to try updating the BIOS first. But that's not an option now because I don't have a video card. I'm waiting for a DirectX10 card <$300. And I'm no too keen on the idea of using my old PSU to temporairily power my new system so I can update the BIOS. My old PSU has a 20-pin ATX plug, is this safe to use with the 24-pin socket on my new board?