Problem with temps (amd 3500+)

[Avengeance]

Well my dads gaming computer is having some problems with its temps. Right now it is fairly cool in their house (70-74F) and the computer is idling at 65C. I took off heatsink and re-applied thermal paste. Still getting temps that are too high. It is running a arctic cooling freezer 64 pro. It works well in mine (4200+ x2) Anyway, does anyone know why this would change all of the sudden? It used to run fairly cool and never overheat.