I know the Macbook Pro suffers from an optical drive issue. Suspect that it's got stuck on eject. Try inserting a cd into it and ejecting it (make sure it's a cd you dn't ever want back). It could also be a failed fan. Check the grilles which are on the back, where the screen hinge is. Yep, the G4 powerbook does do this every time it's powered on. First thing it does is ensure the optical is cleared. Also check it's not comming from the speakers- there could be a sound issue
Edited by richardtj, 19 September 2010 - 02:56 AM.