Is SP1 the usual buggy crap microsoft fare?
It just seemed too much of a coincidence that all this happened just after i updated it. I have updated the Nvidia drivers and will do the rest soon. Hopefully that'll sort it.
The system is OC when I bought it, but it is only the CPU multiplier and that is usually throttled anyway. I'm running Avast antivirus. System has been totally stable until this happened.