No beep on POST

Hello,

A new build. I install the motherboard, CPU and fan, RAM, power supply. Green light on mobo comes on

I then connect mobo to monitor (VGA) and keyboard (USB 2)

I turn PC on and get one long beep followed by two short ones. CPU Fan spinning. I haven't installed a GPU and the monitor is connected to the VGA port of the mobo.

Not knowing what to do I then reseat the ram and CPU + fan.

No beeps this time yet still no display on the monitor and no keyboard led. CPU fan spinning and mobo light on.

Remove the RAM and get the 1 long and 2 short beeps again.

Put RAM back. No beeps but still no display or keyboard

Any ideas???

Thanks very much

FYI: Pentium Dual Core 2.4 G530, Asus P8H61-MX USB 3.0, Crucial 2GB DDR3, OCZxStream 500 Watts.