My new rig won't boot.

[DobyMick]

My new home built computer is not booting.
Here are my parts.
Asus P5Q
WD 6400AAKS
Intel E8400
Xigmatek HDT S1283
G.Skill DDR2 1066 2x2Gigs
Visiontek HD4870
Corsair 750wat PSU
Antec 900 case
Light ON DVD burner

I assembled all of the parts and when I first turned my PSU on the motherboard light lit up green. When I pressed the computer power button on my computer case the motherboard light flickered and all the fans on my system started to move then they just stopped. I decided to trouble shoot by constructing the computer out of its case. I had the motherboard, cpu, heatsink, one stick of ram, GPU, and PSU all sitting out. When I powered this on with the one stick of ram it booted and I could navigate my bios. I put the system back together in my case and it booted just fine. After this I decided to change some fans around and after disconnecting two fans the computer refused to boot.
This time when I reconstructed the computer out side of the case it would not boot. I thought it might be a ram issue so I bought some corsair dominator DDR2 1066 2x1gig memory. This did not help, trying to boot with either of the one gig sticks had no effect.

I have looked at this thing and analyzed it till I am almost crosseyed. It seems that a component went bad or I have my mobo shorting out/grounding somewhere and I am at a loss.

I realy appreciate all of the help guys, thanks in advance

 

[roadrunner197069]

Reset cmos.

Asus boards sometimes are picky and dont like ram volts over 1.9-2.0

 

[DobyMick]

Thanks for the reply

I tried reseting the cmos however this had no effect and the system did not boot.
Is my motherboard dead? How do I know its not the PSU? My other question is how do I know that my CPU is not damaged?