Problem with new built compu

I set everything up, plugged the stuff in, double triple checked the wires, etc.

When I click power theres a flash, the fan works for a split second then stops, my post count stays at 83( atx power suply ready), then nothing happens, my keyboard led is on, monitor doesnt show anything, power button isnt glowing, hdd isnt spinning, fans not spinning.

Any ideas what it can be?

mobo--> abit an8 ultra
card- 7800gtx pcie
processor--> 4200 amd64 x2
ram--> ocx gamer gold 2-2-2-5 timing, dual channel (1gig)
psu--> ocx 520w

Common problem is shorted motherboard. Loosen all the mountings screws a bit on the mobo and see if that helps.

unscrwed everything(mobo just lying on the spacers), still same thing a flash post count 83.

side note no flash occur if its just the mobo, and case leds that are being powered, also fans. power button--> pots code 8.3 and nothing else.

My friend had a similar problem, unplugging his X800 would allow his pc to boot. Once it booted, we turned it off and re-plugged the video card, and it would start up fine.