By the sound of things you have a more serious problem than the icons not showing.
I would suggest removing the motherboard with CPU, heatsink, fan, buzzer, one stick of memory attached and connect it up to the PSU outside the case. Follow these instructions:
Make sure that you observe anti-static precautions.
Lay some cardboard or use the motherboard box that is non-conductive on the worktop and remove the motherboard/CPU/heatsink/fan/buzzer/one stick of memory and PSU from the case and put it on the cardboard. Add the keyboard and now I know you haven't got any graphics but try and boot. The system should try and then fail emitting a series of beeps. Please post what sounds it makes.