Power problem with a new Computer

[Vando]

I am currently trying to build my brother a computer and am running into a problem(obviously). When I turn the computer on via psu switch all that happens is the cpu fan twirls for maybe 1-2 seconds... then nothing. Turning it off then on repeats this.

As far as I can tell everything is plugged in correctly. In trying to trouble shoot I only have the cpu and ram plugged into the motherboard. Nothing else is connected. I am running out of ideas and would appreciate some suggestions.

The system is -
ASRock 939Dual-Sata2 Motherboard
AMD Athlon 64 3500 Venice Cpu
eVGA Geforce 6600 256 Video Card
1 1gb stick of Kingston DDR400

The power supply is not new but I have tried 2 different ones and get the same problem. Both were 420 watt.

Thanks

[jcnoernberg]

you may have a short on the motherboard which means, time for a new motherboard!

unplug the PSU from everything. Plug in one harddrive to the PSU, now, take the motherboard connector and short the green wire to the black wire with a paperclip. This is a simple way to test the PSU. If it's good, it will turn on...

[Vando]

So if I can be sure the psu is working, the only possible thing wrong is a broken motherboard?

[DrKaufman]

When you installed the mob, did you use theose spacer things to space the mobo from the case, or did you just screw it in? If you didnt use the spacers, that's most likely your problem. It happened to me to.