[Tee]

Be sure that the speaker lead is connected to the proper connector according to the mobo manual. This can be helpful because all mobo's will alert you to startup problems (memory mismatch, bois corruption, no video chipset,etc) via beepcodes that can help lead you in the right direction.

Understand that all the new motherboards use momentary shorting to start the motherboard and signal the PS to activate. Be sure that you have located the right power pins on the motherboard's combo connection array and then simply short the two pins together with a metal object (momentarily) and see if the motherboard and ps turns on. You can use a screwdriver or tweezers.

Also, pay close attention to the standoffs that you installed in your case. If they came preinstalled, be sure that none are positioned as to short a run on the motherboard.