Computer Starts for 1/2 second and stops

[TireRobot]

My computer starts for half a second (CPU and case fans start spinning) and then stop. I have removed all connections and extracted the motherboard with the same results with solely the CPU, CPU fan, and memory. I used a second power supply, same problem. I purchased a new motherboard, same problem. I removed/switched the memory, same problem. I started without the CPU fan plugged in, same problem. I removed the CMOS battery for an evening, same problem. The only common denominator is the CPU. Is the CPU a possible culprit.

Motherboard: ASUS P5Q-E and P5G41-M LE/CSM
CPU: Core 2 Quad
Memory: DDR2 1066

 

[ubercake]

Are you using on-board video? Or a video card? The reason I ask is I had a bad video card, once, that wouldn't allow the PC to start. I replaced it and it worked.

 

[kajabla]

Sounds like the CPU could be overheating. Did you put the heatsink on right, thermal compound and all?

 

[Mousemonkey]

Best answer selected by mousemonkey.

 

[Mousemonkey]

This topic has been closed by Mousemonkey