Umm the only other thing I can think of and i'm not sure if this would prevent it from posting would depend on your cpu possibly. Not sure. It ships with a old bios revision that does not have the 1333FSB cpu's configured. So if you have a E6750 1333FSB you may have to borrow a 1066FSB chip to get it to boot. Then you would need to update to P30 for the 1333FSB support.
Again i'm not sure if a 1333FSB chip would boot or not with the older bios.
The PS2 problem is a common among the Evga 680I boards.
If your running a E6700 and a USB keyboard my next guess would be either bad memory/board or cpu. Cpu is unlikely but it happened to me DOA on my first build.
Bad memory you'd have to borrow some or try some other memory out. Like I said though just give me the error code that will make things so much easier. Thank Evga for making diagnostics so easy!