When does it beep? Has it ever beeped?
Now, if it doesnt beep then the problem lyes within the mobo, RAM, or CPU. Make sure you have both power plugs into the mobo, the RAM is fitted into the correct slots, and the CPU heatsink is on properly. When testing, only have the RAM, CPU, and power plugged into the mobo. Leave the video card out. We are just trying to get the mobo to give us a beep.
Also, why are you sending it back to ASUS? Why not send it back to where you bought it from? Maybe they'd get it to you faster.