Hi, I have a 2 year old titanium Powerbook running Jaguar. Since yesterday, it keeps freezing, maybe a half hour or hour into use. All the programs stop running, cursor stops moving (sometimes it disappears altogether), and it stops responding to keystrokes. Usually just Mail, iTunes, AIM, and Safari are running when it happens. One friend thinks I should buy Norton and defrag the HD, another thinks that maybe my HD has overheated. Does anyone have any other ideas? I would run the Hardware Test, but I just lost the CD when I moved last month. The powerbook has all its original hardware, but I added an Airport card a few months ago. Thanks!