Gigabyte GA-P35-DQ6 Motherboard Dead

[Vicious]

Good evening,
I have to repair the pc of a friend.
Config:
Gigabyte GA-P35-DQ6
E6850
2gb crucial Ballistix (double sided) PC8500
POV 7300GT
Corsair HX620W
2x WD Raptor 74gb raid 1

(optical drive (but hey, not fed during tests therefore ^ ^))

Problem:
The PC runs for 5-6 seconds and then stops. The CPU fan wants to start but is not (frequent stops, few times). The PSU seems to be slow as well. I tested with an alim 300w (nothing else on hand) and the same thing. I tested another, same with normal PSU (Reminder: 620W). Nothing is fed from the 2 HDD (WD Raptor 74) raid.

In view of the tests, the PSU seems irrelevant. It remains the motherboard.
what do you think?

thank you for your help

[ApPy10]

Just out of curiosity, you tested by making a clear CMOS?

[EINSTEIN_007]

Do you see anything on the screen?

[Vicious]

not tried to clear cmos, I forgot it ...
and not anything on the screen ...

[techman]

Doubtful that the CPU is dead. I would definitely swap in a known good power supply though to be sure. Also, have you reset the CMOS?

That "test" method, doesn't do much since it can't properly put a load on the power supply. I've seen bad power supplies as well as motherboards cause the symptoms you describe.

Also, the proper way to reset the CMOS is by shorting the right jumper on the motherboard. Try that method as well.