Hello, I have an iBook G4 purchased about 1 year ago. The sum problems I had until a few weeks ago were a couple of frozen applications that I had to force quit. Then I tried to install Skype. 2 minutes after opening Skype the dreaded "You must restart..." message appeared, indicating a kernel panic. My first action was to restart and uninstall Skype, but the problem has persisted. The kernel panics continue without any clear pattern - the attacks have occurred variously when running Firefox, iTunes, and Word. I have tried pretty much every trick recommended in the Mac Help files- reselecting the startup disk (holding X while restarting), restarting holding the option key and selecting the startup disk, and also resetting PRAM. The disk utility could not detect any errors on the startup disk, and I also used Disk Warrior. Again no problems detected. Thinking it might be hardware, I ran Apple Hardware Test, still no problem detected. Since then I did an Archive and re-install of OS X 10.4.2, and the kernel panics continued. The last thing I tried was a full erase and re-Install of the operating system. This was working okay, but as soon as I had finished setting my preferences again - BOOM, kernel panic attack. I live in a smaller town, and the only authorized Mac repair agent will charge $85/hr for software related problems, so if you can think of anything else please post!