Thany you. I have tried this. The fan is spinning and locked down.
I get four beeps when switching on - then the cpu fan starts and then the pc shuts down.
I tried one stick at a time putting each stick in each slot separately. I got four slow beeps and then a continous beep and no start each time. I put all the memory back and now I am back with four quicker beeps and then fans on and then switch off.
No beeps - cpu fan starts and then slows down but continues to spin.
Video is Ok and the whole PC booted into windows and loaded some drivers. I closed and re-started and again all OK.
I think we can close this now and thank you very much. I bought two brand new memory sticks and I would not have thought of it. This is about the sixth or seventh PC I have built over many years and they have always worked first time.