So when you press the power-on switch, the front panel power indicator LED does not turn on? I guess the first thing I'd check is to make sure that the power-on switch is correctly wired; that is, when you press the power-on switch, pin 6 of the front panel header should be pulled to ground. If that is happening, then a completely silent board suggests strongly that you have a bad board.
Hi Clint, I checked the wiring of the power on switch that was right - so looks like most likely a bad board.
Could the problem be caused by a bad CPU - ie if the CPU was defective would that stop the mobo from beeping or the fans from whirring or....???