|When a power supply goes out it often damages other hardware. Usually it's the motherboard. In your case the motherboard seems to be OK, at least enough to do the initial posting, so maybe it's something else.|
If you have any add-on cards, temporarily remove them in case the problem is with them. Disconnect all the drives too.
Somewhere on the motherboard there should be a 'clear cmos' jumper. With the power cord disconnected jumper it to the 'clear' position for a few seconds and then back to 'standby'. That will clear the cmos/bios setup settings. The problem is probably not with those settings but sometimes it seems to work. You may need to consult your manual for the jumper location.