Have a look at this diagram:

http://www.hardwarebook.net/conn...r/ atxpower.html

You can "power up" an ATX power supply by wiring pins 14 & 15 together.

Also, you may want to investigate the capacitors - I've had this problem before - if they appear bulgy, and are leaking it is likely that you've found the culprit.
Jan | Homepage | 06/12/01 - 10:12 pm | #

Try disconnecting everything possible and booting the bare bones machine. disconnect all drives, pci cards etc, then try powering on and see if the cpu fan spins up. If it does, reconnect things one at a time to find the culprit. If one component shorts it can stop the whole setup from booting.

If it wont boot like that then either your psu or your mainboard are fried

good luck
Sean O'Donnell | Homepage | 06/12/02 - 12:03 am | #

I had four out of five AthlonXP mainboards die on me after roughly a couple of years' usage, with similar symptoms, so the odds are against you.

Before giving up hope though, try removing all drives (disk and optical), any extra fan it may have installed reinstall the gpu and the ram and try the 230W PSU again. It should have enough power to operate those components to check the mainboard.
Stavros | 06/12/02 - 1:36 pm | #