I have searched many forums and talked to fellow macbook owners, some have the same problem - some not. The HD crashed about 2 years ago, and since the replacement (TOSHIBA MK6034GSX 60GB) the CPU will go very hot 80+C and the fan going to 6200rpm if visiting some internet pages. Normally a problem if (when) the kids are playing free online games or visiting youtube or similar. Made a screenshot, notice CPU usage around 112%, smartfan showing 70C and 6200rpm. I have taken the mac physically apart and cleaned the cooling duct and applyed new thermal paste. Didn't help. It drives me crazy, I hate noisy computers, any ideas?