the motherboard has an undetermined fault and should be replaced. I had my CPU overclocked to 3ghz when it did this but have set it back to stock since but still get the freezes. Never had anything else overclocked. Have tested if it was the psu but concluded it isnt because i used my friends brand new hx650w corsair and had the same problems except this time it didn't freeze until the second i stopped the prime95 test. Could it be the CPU? i wouldn't have thought it would work at all if it was. My pc works fine for normal internet and music but thats it. Any suggestions?