I have an iBook G4 1,2 ghz with a 60g HD and I have a constant "buzzing" sound from the left part of the book, where the hd is. Whether this is the fan or not I'm not sure, but it's starts as soon as the machine is switched on. I also imagine it wasnt constantly on before, but i might be mistaken. Is this normal? The sound can be quite annoying if I work in complete silence but with background noise it's not that easy to hear. Any way to "fix" this?