I recently bought a new motherboard, as my old one had blown some capacitors. I replaced it, and seated everything in place. Once this was done, I connected all wires to see if it would power on, and got nothing. After that, I dumbed it down and unplugged everything; only connected the power swtich wires to the motherboard (pins 7 and 17) . I pressed the power button, only to receive no power at all. This worked with the power wires in both positions.
The wiring picture there is how mine matches up - the motherboard is a TMC T17NBF Socket 370. I purchased it off Ebay, but it should be fine as the seller is at 100% for a rating, and sells tons of motherboards.
If you need additional information to help me out, I'll be glad to give it.