Ok guys, its not a software prob as it crashed on new install on new hd
i think i have found the answer, Although the ram testes completed and passed it seems to be the 4th GB in the 4th Socket. I installed each stick one by one until it fell over. On the 4th stick it froze again. removed the 4th stick and its been stress testing for about 1 hour and half now, just a waiting game now to see if it keeps it up.