Just like the title says, my sister's iBook G3 (800 MHz I believe) never turns off its fan. It is as loud as when you put in the hardware test CD. Sounds like an airplane engine. I've got all the software updated, have restarted, logged out, repaired permissions... I don't know what else to do. Anyone else have this problem and know how to fix it? The logic board was replaced once by the previous owner (our cousin) but it seems to be fine. Would zapping whatever it is fix it? Please help. Edit: I see this has been moved. Sorry... I thought it fit under Mac Hardware?