Thanks for the info,it would seem to be motherboard related,had a poke round in the back and found restrictive jumper settings for the processor.Taking memory out didn't resolve the problem.All fans working correctly (plaster firmly affixed to index finger now as proof).Time for a new mobo methinks.Unless FL310 . .you wanna donate that system you have on test!! <img border="0" title="" alt="[Big Grin]" src="biggrin.gif" />