Help! New Build Won't POST

[Detson]

The PC I'm putting together for my brother: C2D 6400, Biostar TForce 965pt, PQI Turbo DDR2 667 RAM, and NVidia 7900gs, refuses to POST. The power is on, the fans spin, but everything shuts down a few seconds after powerup, only to restart after a second or two. There's no POST beep of any kind, and no image displayed on the monitor. I've tried swapping a working ATI x800xl, to no effect. I've also tried running the PC with only the RAM and CPU installed, and with just the CPU, but I still can't get POST. Help!

 

[Detson]

Yep, checked all that. The PSU is 380 watts, with 18amps on the 12v rail. That's less than the Nvidia GPU demands, but that same PSU supplied my ATI card for a year with no problems. I even tried booting up outside the case itself, to check whether or not it was shorting out.

 

[locky28]

Pull the GFX card out and try booting to see if it still does the restart thing still. This will determine if it's lack of PSU juice.

 

[BustedSony]

Yep, checked all that. The PSU is 380 watts, with 18amps on the 12v rail. That's less than the Nvidia GPU demands, but that same PSU supplied my ATI card for a year with no problems. I even tried booting up outside the case itself, to check whether or not it was shorting out.

You still didn't say what brand, but I'm betting it's an Antec power supply. Anyway press and hold the keyboard "Insert" key immediately after turn on (bottom right) then press delete and go into bios if you see the POST screen. Pressing insert is a warm reset that clears any possible conflicting resource assignments.

 

[Detson]

Thanks for all the great ideas, but my brother is getting impatient; I think we'll just RMA the motherboard and get another one. Any recommendations for an inexpensive C2D mobo?