New Build Won't Stay On

[shiftkey]

I just finished a new build and plugged it in for the first time. I turn the power supply switch in the back on and an led on the motherboard lights up. When I press the power switch up front the fans spin and lights on the front panel turn on, but then everything stops after a few seconds. The led on the motherboard stays on though, as long as the main power supply switch is on. Nothing displays on the monitor. After a few times of this, I smell something strange, burning probably, but no smoke. It still acts the same and no worse.

My friend suggests that it might be the power supply, and that it may have burned out. I've read that the psu is often the trouble, but it still seems to be working(somewhat). I also just recently read that the psu is actually only 400w, which from what I've calculated, would barely be suffcient.

Any ideas?

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ASUS M2N-SLI Deluxe
GeForce 8500GT
FSP Group (Fortron Source) AX450-PN 450W
AMD Athlon 64 X2 6000+ Windsor 3.0GHz
CORSAIR XMS2 1GB RAM x1
Western Digital Caviar 320GB HDD
SONY NEC Optiarc DVD Burner AW-Q170A-B2

[blue60007]

Try this:
http://forum.pcmech.com/showthread.php?t=132409

It could be a bad PSU, but you have a good brand. That'll reduce the chance it's a bad PSU (but still possible).

[shiftkey]

I tried just buying a new psu (Antec Basiq BP500U 500W) and now nothing turns on, except the motherboard light. I switched in the old psu and it still won't turn on.

[flanzig1]

Make sure your doing the testing as per the link Blue listed. This eliminates any possiblity of the motherboard shorting to the case. Since you smelled something burning, you need to find the source of it. From the discription of your first turn problems, you either didn't have all the needed power connections from the PSU to the mobo or the CPU heatsink wasn't correctly mounted. Since you kept on trying to start the PC after getting the burning smell, could have damaged other components.