New build only the power LED only thing working.

Solution
Well you got 5v !

Simple. Unplug EVERYTHING. Boot bare mother with CPU (of course), no ram, no HD, no nothing. Attempt to get into BIOS. What are the fans doing? Any beep (hook up speaker if it needs it).

One thing people forget to do is to connect the 4/8 pin extended power (12v) cable. Make sure the 20/24 pin PSU cable is down all-the-way, if too tight feel free to place something non-conducting under the Mobo's connector so you can push down the PSU connector.
Well you got 5v !

Simple. Unplug EVERYTHING. Boot bare mother with CPU (of course), no ram, no HD, no nothing. Attempt to get into BIOS. What are the fans doing? Any beep (hook up speaker if it needs it).

One thing people forget to do is to connect the 4/8 pin extended power (12v) cable. Make sure the 20/24 pin PSU cable is down all-the-way, if too tight feel free to place something non-conducting under the Mobo's connector so you can push down the PSU connector.
 
Solution