whats dead? opinions please

ok so here is the thing. My desktop is dead and I am not sure what exactly died. I think its the mobo but I am not sure

so first off the specs
pentium D 2.8 @ 3.6
Asus P5WD2-P
PQI ddr2 667 (2 gigs)
ATI Radeon X600
Seagate 300 gig SATA HD
OCZ Powerstream 600W

Under the current water setup

BIP II with 2 deltas and 2 thermoflows in push pull
D5
MCW 6002
3 delta case fans to move the air around

so I was playing some CS: Source taking a break from work and everything was fine no problems. I shut the game off and go back to work and when I come back the computer is locked up. So I restart the computer and no signal to the monitor so I swap out the video card with my GTX and no signal.
So I started unplugging everything thinking that the board for whatever reason wasnt getting enough power. Then I changed the power cords running to the board as much as I could and still nothing. I also tried resetting the CMOS and popping the battery

so obviously something is dead. I get no beep codes so I am guessing its the mobo.

Opinions? anything I over looked? any advice would be appriciated

Hmm.. odd.. Same exact thing happened to my pc a few days ago, no signal to monitor, no beeps. I finnaly figured out that my TT BT had gotten so loose that the CPU was overheating and it would not turn on

So re-seat your HS and also try running it with only 1 stick of ram

in my case it seemed to be the North Bridge. I forgot to mention that it was under water as well. The springs were so tight that it had actually pull its anchor off the board. From first inspection that was not evident.
Anyways I replaced it with the stock one and everything seems fine now

thanks for the tip

Might be the psu-

Disconnect teh psu from all of your components and short the sincle green wire in the main connector to any black wire- this will signal it to start up. Then turn the PSU switch on and see if it powers up. You can use a paper clip for this.

If you have a multimeter, check the voltage at a molex connector, black>red and black>yellow- you'll read the 12 and 5v rails.