hello i recently purchased a used g4 powerbook. it is in excellent condition, however it sometimes makes a buzzing sound. i first thought it could be a fan but now i think it could possibly be the hard drive. the noise comes from the front of the powerbook and sounds like it is near the trackpad or dvd drive. from what little i know about this unit i think the fan is farther back. im wondering if something needs to be cleaned out or if i need to replace the hard drive please help with any suggestions!