This morning, PC powered on, no beep on post. Checked the MB warning lights and CPU and RAM where flashing on and off. Did all the usual, pulled things out, tried with one ram slot, re seated CPU etc. Phoned OCUK to RMA and that was in place for MB, RAM and CPU. (Great customer service there btw!) So I started to unplug headers, etc. but continued to do more digging and found if I removed the RAM completely, the system would give me memory error beeps suggesting the CPU and MB were communicating. Some posts suggested the PSU so as it's a modular PSU I tried a different PCI cable and it posted! Woo. Started to plug things back in... failed again. Turned out it was the front panel connecter that seems to have failed. I plugged the front panel cables directly into the motherboard and all seems well. 30 years pc building and still learning