Coming to you live from another computer!...

i would try a new power supply first. i don't know what kind you have, but if it's a generic crappy one, you'll want a better one anyway. maybe test with a different power supply that you know works. on this note, you can try unhooking the power from all the drives and just have power go to the motherboard.

if the psu isn't dead, this could either be the cpu OR the motherboard. the easiest test would be to replace the cpu with another of the same socket type. maybe your dad's dell will work (this is getting into risky territory, though, as you may void whatever warranty he might have).

if the cpu replacement doesn't work, then it's the motherboard... if you replace both, you can then find out which one really was the culprit and sell the other working part.

Jam it back in, in the dark.

your dad has a dell, right? you could try using the dell one, and JUST connecting it to your motherboard to see if it will post.

if it will, it's the psu, etc.... you already know that.

There's nowhere I can't reach.