Does the computer beep at you? If so how many beeps, it's important. If you don't have a speaker installed, put one in and see how many beeps, that'll help you greatly in getting to the root of the problem, in the mean time check over wires and stupid little things you may have missed or messed up.
The fans work fine, I haven't been able to hook up a speaker yet to test tones. But a red LED in the front panel lights up immediately, BIOS isn't starting.