When it is left running it will shutdown and start itself up again an hour later. Temperatures have been checked and are all at a normal level. Was thinking PSU but its new.
Boot into safe mode to see if it is a hardware or software problem. Check to make sure all fans are running. There could be a broken fan causing overheating. Ensure no connections are loose in the system. If it is a hardware problem and these measures did not help, a faulty motherboard could be responsible.