Some help and advice about CPU and MOBO

[the last resort]

This past Sunday my computer went out on me. Most heartbreaking thing to recently happen.
I have come to you guys once again for some help. First I will list my current setup:

AMD 6000+, stock clocks/lowered voltage.
ASUS M2N SLI Deluxe 560-SLI MCP
6GB of Corsair ram, mix of 4GB of Dominator 1066 and 2GB regular at 800.
Visiontek radeon 4850 overclocked to 690 on the core, 1010 on the mem.
Apevia case, modded.
Thermaltake 750W modular PSU.
One WD Caviar Black 640GB hard drive, and one 160 WD caviar.
One SATA DVD burner from LG.
Aftermarket cooler on the video card and processor.
4 120mm fans in the system total.


Here is the problem and the steps I have tried to solve it:

It seems to me that I have a bad CPU and/or motherboard. I had it working just fine Saturday night, but powers off just seconds after boot on Sunday. So far I have:

Pulled out all fans. Same problem.
Unplugged the DVD drive. Still doesnt work.
Unplugged the hard drives. Still wont work.
Took out all ram and tried one stick at a time. Still doesnt work.
Took out the video card, still wont work.
Took off the heatsink on CPU and cleaned/reapplied thermal paste. Still doesnt work.
Tried different power supply. Still doesnt work.
Unplugged everything except one stick of ram, still wont work.
Tested the power switch, it is electrically OK.
Tried booting without switch, still comes and then shuts off 4 seconds later.
Reset BIOS, still doesnt work.

I tried on a different computer what I thought was happening: when the computer comes on, the power switch is pressed, and then shuts off because the switch is still pressed. Exact same timing, but the power switch is completely fine.

When I try to boot, all hard drives and the DVD drive spin. All fans spin. There is no error from the motherboard, and the green LED signaling power-good is still lit.

So this is the point where I ask for some help. I know that this post was very long, but I figured I needed to get the necessary information out there. I would like to know what you guys think and any suggestions you guys my have for fixing it. This coming Saturday I will be taking it into the basement and laying everything out on cardboard to see if the case is a problem. A huge thanks in advance for all help provided.

 

[ravenware]

Check for bulging capacitors and char marks on the motherboard.

Did you try plugging the machine in another outlet in a different part of the house?

 

[the last resort]

i checked on the motherboard, no bulging caps or char marks. Everything looks perfectly fine. I tried plugging it in to a different outlet in a different room on a different breaker, and it still doesnt work. Hopefully someone has some info that can get this working, not really wanting to buy new stuff. (although a new MOBO and the Phenom II 940 would be totally sweet!!!)

 

[the last resort]

i think i found the problem. apparently the front USB ports were plugged into the FireWire port on the motherboard. Hmmm. Don't recall doing that. What a bummer, and a dumb wasy to fry you're motherboard. Thanks for the input guys.