New build won't post

First I'll let you know the hardware. Everything but the motherboard and power supply was purchased brand new today.

Intel Dual-Core e5300 processor (2.60 GHz, FSB 800 MHz, Socket Lga775, L2 Cache 2Mb)
Asus P5N-E SLI motherboard (FSB 1066 MHz)
Corsair 2 GB XMS2 2x1024 6400C5DHx G ram
Seagate Barracuda 1000GB hard drive
BFG Tech GeForce 9800GT 1GB video card

For the power supply, a 650 watt BFG was used, fans would spin for a second and then everything would die. LED light on motherboard would stay on. No drives came on.

So I put my old power supply in (enermax noisetaker II, 485 watts) and fans and all drives spun. (Note that the video card does not require additional power.) No beep from the motherboard, no response from the monitor. A bench-test was performed with this power supply, both in-case and out of the case the same problem is occuring.

I removed the CMOS battery for ten seconds and reset, I switched the positions of the RAM, I tried one stick of RAM, video card has been reseated multiple times.

Any clue as to what it could be? Is the motherboard toast?

Look forward to your help,
Lauren.

I've already gone through the checklist, that's how I found this site.

There is no onboard graphics port. The case does have a speaker that worked prior to installing the new parts. The speaker is connected properly and there are no beeps.

check the ram, make sure ram isnt doa, try boting 1 stick at the time.