| If it is heat (as I've recently discovered), it may be due to the fact that there wasn't enough Heat Sink Compound applied to the top of the processors heat plate. Thats the little raised square in the center of the processor, which makes contact with the heat sink.
This is, of course, provided you built it yourself. If it was pre-assembled and it turns out that it was infact due to the lack of compound, then I'd probably have a word or two with the stores manager. |