Computer wont boot

[Stevonio]

Just built a new computer for a friend tonight.
When I turn it on, it either
A.) 75% of the time powers up for a second and turns off
B.) 25% stays powered up, but no video signal.

It is a..
Abit KN8 Ultra Motherboard
BFG 7950GT PCIE
Thermaltake 500w PSU W0093RU
1GB Patriot RAM
WD 250GB HD
NEC DVDRW
AMD64 X2 3800+

I tried it in the case. I tried it with the mobo/cpu/ram/vga hooked up outside and it still does that. I was thinking a motherboard short in case but I guess not?

The VGA and the PSU both should be compatible from what I read.

Any suggestions? Or do you think I should RMA PSU to newegg for a replacement?

 

[l3ored]

sounds like the mobo to me. can you find another one to swap and test it?

 

[Stevonio]

I installed another PSU today - more powerful then the last. It still does all that, no video, turns on and runs sometimes (no video), or it just turns off then on.

Thinking its the mobo then?

Stevo

 

[nchavie]

Sounds like the motherboard is shorting out. Did you remeber to put in the copper standoffs? Or those little red disks between the case and bottome of the motherboard (they go around the screw so the mother board isn't actually touching the case).

EDIT: Sorry I just read that you tried the mb out side the case...do you get any post beep errors?

 

[Stevonio]

No beeps at all. If it stays powered up, it just sits there.

I sent my friend out to get a new motherboard. I hate computers. We will see how this goes.

Stevo