Need some advice on a computer problem

[Xtahse]

I'm having a computer problem which I'm kind of stuck right now.

Long story short

-ASUS Xtreme Striker II motherboard
-Thermaltake Toughpower 1200W PSU
-2x GeForce9800 GX2
-OCZ DDR3

so the problem is when I press the power botton the computer would turn on for 0.1 seconds (LED lights on, Fan starts to spin) then powers off.

Sure thing, PSU probably defected, changed to a new one (same model&make) computer turned on the first try! So I started to wire the cables and tidy things up. After I still feel a little skeptical so I tried again - sure enough it turns on but I forgot to plug in the keyboard so I shut off the power and proceed to plug in the keyboard. Turn on the computer, the problem I originally had reproduce itself. Now I'm having the power problem all over again.

There is a way I can turn the computer on is by pressing the "clr cmos" botton on the back of the I/O panel. But, after I turn it off it would not turn on again unless I press the clr cmos botton again. This method works about 4/10 times.

*note If I use the SPARE enermax 600watt PSU the computer turns on everytime.
** I have seen it happened where the PSU & MOBO just not compatible (could it be the problem in my case?)
*** I have 2 thermaltake 1200 watts PSU - tried both of them - problem still happens

So any advice?

Thanks in Adanced!

[Bomberman07]

If I understand you, when you try to boot with the thermaltake, the computer shut off itself, but when you use the enermax it boot ok?

Seems like you founded the problem. I think you need a new psu ( no sure if a 600w is ok for sli..). Is the thermaltake under warranty or something?

[Kakarot]

I would build it outside the case. I had a short do this once

Gl