I'm having the exact same problem with my Asus P5N32-SLI Premium.
I'm doing upgrades on an old system, got said board with a Core 2 E6600 (bought seperately, not as a pre-built combo).
Rest of system:
Video card: Asus EN7950GX2 video card
Memory: Corsair TWIN2X2048-8500C5 2GB Kit DDR2-1066 XMS2-8500
PSU: Antec TruePower Trio 650W PSU
Sound Card: Creative X-Fi Fatal1ty
HDD: 2x 74GB SATA Western Digital Raptor
I've never been able to get a POST screen. My monitor just stays blank scanning for a signal. The power LED on the motherboard lights up, and all fans spin up (including cpu and video card heatsink fans). The power LED on the front of the case lights up for a second and then shuts off.
First thing I thought was CPU. Took it out, checked the pins on the mobo and the contacts on the CPU itself. No bent or broken pins, the contacts are clean, and all the pin marks show well aligned connections. Second was the memory, tried one stick at a time, and in different slots, still no POST.
A buddy told me that he'd heard stories of people not being able to get systems to do initial boots with the 7950GX2's, so I borrowed a 7900GS, still no change.
All signs point to a DOA board, but before I blow $250 on a new one I thought I'd look for help.