I don't have a Windows disc to check with but I took the machine to a local
computer shop for them to check for me as I ran out of ideas and they tested
everything apart from the HDD's. They used Windows (with one of their own
drives). Needless to say I was not happy with them for doing such a
half-hearted job as I told them they could wipe the smaller of the two drives if
they wished (that was when I was using an 80GB and 160GB drive rather than the
250GB and 750GB drive I now use). I have checked power settings but don't think
it is those as it has sometimes happened during installation. I have run the
sensors software but it doesn't seem to be a problem with temperature as it
never seems to get very hot.