I've been working on a new desktop, and I hit a bit of a snag.

Specs:
4GB DDR2, 800MHz
3.14GHz Intel Core 2 Duo (E8500)
XFX 750i mobo
XFX NVidia 8800GT
750GB HDD
680W BFG PSU

The Problem:
The problem is that when I try to turn it on, it powers up, then shuts off a second later. When it does this, the diagnostics panel displays FF (Fully Functional), all of the fans spin, everything lights up and so on. However, after it fails like this, the only way that I am able to try again is by resetting the PSU. Also, when the PSU is turned on (but not the PC in its entirity), a red light displays on the mobo.

Things I've tried:
I've attempted to start up with the bare essentials (mobo, RAM, processor), but it does the same thing. I've tried contacting XFX's technical support about a week ago, and I'm still waiting for a response.

So far, I think the problem lies in either the mobo or the PSU. What does massassi think?

theres a switch on your powersupply that changes the voltage(i think) try switching that then turning it on again.

or possibly a short in the case. pull the mobo out of the case with just processor and ram in it, set it on some static free surface and turn it on. see what happens.

BADBADBAD.

This can fry your entire system and/or make a nice pile of flames/sparks if it is set wrong.

Check the jumpers, too (if it has any). Try disconnecting the power switch and manually jumping it- maybe the switch is bad?

both of my suggestions were solutions to problems i had with my own system builds.

i know the potential for bad things happening is there, but i assume he knows that too.

Check that there is the right amount thermal paste on the PSU fan, it could be overheating and shutting down to prevent damage.

Well, I know about the voltage switch, and have checked for that being set before I put the PSU in... thing is that it doesn't have that on it... so... heh

Also, it has plenty of paste, as far as I'm concerned. Though, I'm not sure it even stays on long enough to get hot... it starts up for a second tops... =/

I'll try these ideas and get back to you. Also, I'll be trying to contact technical support, as I've heard of some issues with some of their motherboards. Want to make sure I didn't get a part of a bad batch or something.

UPDATE: Tried calling tech support. Stayed on hold for one and a half hours without getting a reply. Also, my emails still remain unanswered, as they have for the past week. :argh::psyduck:

Try a different PSU? Try disconnecting everything too, just turn it on with the mobo, proc, and one stick of ram and see if it stays on.