Try a program like Everest Home Edition, it should give you the cpu temps in there.
65 deg C is a bit hot for my liking, does the case has a rear extraction fan or just one on the side?
I don't think the power supply could be possible for the heat, the cpu fan isn't cutting out at all is it?
I would look at reseating the heatsink with thermal paste if you can to see if that rectifies the situation.