my 17" powerbook G4 is 3 years old. It has until now been a great laptop, no worries. This morning it woke me up with the worst noise from, apparently, the hard drive. The noise was a loud, almost grating sound, as if the drive were rubbing on something as it went around. I put the laptop to sleep (it should have been to sleep automatically). Later it wouldn't wake up. I tried a number of things (Apple Hardware Test gave me the 'invalid memory access" message, i started it up from the install CD and then it seemed to be operating again so i repaired the disk--it said that reserved fields in the catalog record had incorrect data' and that there was an invalid leaf count. repaired both things.) I made a clone of the hard drive so i have a backup. But it is still making noises...sometimes sounds like a guitar string twanging or a digeradoo. the sound swoops low as if the disk is slowing way down or skipping. sometimes i get the spinning candy. it goes quiet and then gets very loud. it is very erratic. am i in a death watch? is there anything else i can do besides watch it die? I was in paris about a month ago on vacation and my travelling companion knocked the laptop off a chair and dented the titanium casing in a few places but it has been fine since then--until now-- operationally. any advice?