Until recently, when playing a GPU-intensive game, for example Colin McRae DiRT 2, my GPU fan would spin up from its relatively quiet, slow rotation to a faster, noiser one. Once I had finished playing and closed the game down, the fan would obligingly slow back down to its original rotation.
The problem is that this no longer happens - the fan speeds up OK but will not slow down. The only way I can get the fan to go back to the correct speed is via a reboot; not ideal.
I am running the latest BIOS etc. and from other posts it seems I have a hardware problem - hence my request for information on replacing the GPU and PSU.