Strip everything down, connect the mobo, cpu, psu (make sure you connect both the mobo connetor and the 4 pin 12 cpu lead), then connect the PC speaker connector and on/off switch. Nothing else. The system should then switch on and beep at you. If you don't get any beeps while in such a stripped down state, you have to determine which of remaining parts are at fault.
There's nothing wrong with your spec by the way, the Corsair and Gigabyte boards are really good, have specced several machines with similar config's and they're all running 100%.