Alright, shorting the PSU works, so that component isn't the issue. Anyway to test a motherboard, or am I just going to have to spring for another?
You could spring for another motherboard, a bit costly though, perhaps best to see if a friend can lend you their working PSU and see if the motherboard starts up and try your PSU on their motherboard.
I agree with the previous poster make sure all the cables are plugged right... you could short the two pins to start the board without a switch with everything plugged in properly to see if it will start.