Another ASUS P5N-D motherboard thread that need tech support

Hey guys

I've taking down several computer hardware failure problems on my own in the past, but this motherboard I've been working on the pass few hours and I just can't tackle it. I refuse to RMA because I believe it can work, so I'm seeking help, from one tech to another on this.

I have the following:

Intel E2160 CPU
ASUS P5N-D Motherboard
EVGA 7900GS GPU
Freebie 500W PSU (It's not the problem)


Problem:

Spent the whole day yesterday trying to get the computer to POST, unfortunately removing all Hard drives, ensuring proper grounding, swapping CPU's, PSU's, GPU's, have failed. The POST code is 1 long beep followed by 3 short beeps, Video error. I've used single DIMM memory several times, doesn't seem to be the problem.

Today I made a lot of progress by actually getting the motherboard to pass POST VIA PCI video card, the main problem is that I cannot get the motherboard POST VIA PCI Express 2.0

I've flashed the BIOS to initial and most recent updates, still the same problem. I switched the BIOS to boot from PCI 2.0, still nothing. Pulled the CMOS battery, nothing. There's no problem getting it to boot through PCI but whenever I try using Express 2.0 I get the long beep, 3 short beeps.

Any ideas that can be helpful would be greatly apprciated, if they work or not, thanks.