Quick update, motherboard now back and have fitted 2x8gb of vengeance lpx 2133mhz and still not posting to bios, but now sometimes the psu fan will run flat out and I have to do I hard rest to turn it of, but still not posting to bios. Up until now both sets of ram haven't been on the QVL because I can't get it in dual only quad, the only difference is 1 number (xxxx4M4xxxxx, xxxx4M2xxxxx), so now have ordered more ram, vengeance lpx at 3000mhz because it's on the QVL. So it's arriving tomorrow and I will give it a try if it doesn't work It has to be the cpu, I just can't understand when I was able to get windows installed and up and running for a while before this happened.