If all your connections are right, then the only thoing you can do is remove everything from the case that's not necessary. Leave just a stick of RAM, the graphics card, and the CPU, and see if it boots.
If not, you can try reinstalling the CPU. This is unlikely the problem, but you can try it as a last resort. If that fails, then one of those peices of hardware is to blame, or JBI's suggestion is on the money.
Alternatively, if you have a spare CPU laying around that you can flip into the mobo, I'll second JBI's motion to give that a try.
EDIT: Or call ASUS first thing tomorrow. good idea.