Either the board or power supply is bad. If the board is a btx format, then it's time for a new system. Frys has some for $228 tomorrow if you live in the usa.
How can I tell which it is .... there is still a green light on the motherboard ..... should I assume that it is getting power from and operating power supply unit?
I don't know what a btx format is
I've ordered a data recovery cable to try to get my files while I figure this out http://www.ClearClickSoftware.com