I'm putting a new PC together now. It worked fine when first turned on. I changed the BIOS settings some (turbo mode, etc.), put in the Win2K CD-ROM, rebooted, got a BIOS message that the floppy drive failed (noticed the power cable wasn't connected), Win2K started booting from the CD. I hit CAD to end the bootup, then turned the power off.

I connected the floppy power connector, powered it on and nothing. A LED lights on the motherboard, but the PS fan doesn't run.

:-(

I'm in the process of diagnosing it. I suspect something died in the PS.

PC Power and Cooling has an ATX power supply diagnosis page [link|http://www.pcpowercooling.com/support/index_ATX.htm|here] that I'm going through now. Maybe it'll help you too.

{added in edit}

< a few minutes later... >

In my case I didn't need to go through the PS diagnosis.

Since the system worked before I plugged in the floppy power connector, I unplugged the floppy power connector and powered the system up. It came up fine. I then turned it off again, reconnected the floppy power connector, and powered it up. It again came up fine.

I suspect that I didn't have the floppy power connector installed correctly, or gremlins....

I hope you figure out what's happening with your system.

Cheers,
Scott.