I have a 1.67 GHz Powerbook that is just over a year old. I'm running 10.4.5. Occasionally the Powerbook has run quite hot for a day or two then settled down again. It was one of the ones that had the replacement battery under the recall programme, though I've never had a problem with either. It had had a long period of running quite cool when I took it back about a month ago for a replacement mother board. It was fine still when it came back; the only thing I did between it being cool and being hot was shortly afterwards to completely discharge the battery and charge it up again. The heat is concentrated at the back of the powerbook and the fan/s are constantly on. The only thing I've downloaded recently is Audio Recorder 3.0 but think this problem precedes that. I've repaired permissions since the download but am not a techie so not sure what to do next. Any suggestions please?