If you are absolutely sure you have everything hooked correctly, I would remove the board itself from the case, only hook up the power supply "which may be bad" and jumper the power switch prongs, see if it fires up. If not, it could be a bad motherboard or DOA as we like to call them. This is not uncommon to get a new MB that is bad, it happens with every company and just depends if you were the unlucky one.

So aside from trying another known good PSU with that motherboard, I would say it's time to find your packaging slip and contact for a return.