Right, thanks for all the replies.
About my pc's specs, it was meant to be in my signature. This happenes every now and again. I will open msi afterburner and check if it is my GPU fan.
My pc:
I5-2500k @ 4.6GHz, Asus P8Z68-V Pro, Asus gtx580 Direct cuII, Corsair Vengence 8gb 1600mhz, Corsair AX850