Hi. I'm running Panther on a revision C 12" PowerBook. I've had it for a few months, and so far everything has been great with one exception: after using the PowerBook for awhile (hours and hours), the Dock will fail to appear when called with the mouse pointer, and Exposé no longer functions. I also cannot restart, log out, or shut down when this occurs (it begins the process but hangs, spinning the beach ball for awhile and never actually shutting anything down). Everything else seems to function normally during these episodes. I believe this started happening after installing some app that "unlocked" "hidden" features of the OS, namely additional minimization animations and an alternate way of revealing the desktop through Exposé (shrinking all the windows to what was essentially an icon on the desktop, instead of pushing everything out to the edges of the screen). I ended up ditching this software because it would often lock up in the midst of minimizing or using Exposé. I also discovered that it was optimized for a previous build of Panther. Of course, for all I know this has nothing to do with it, but I am fairly certain it does. I am wondering if anyone can think of a simple fix for this, perhaps a preferences file that was altered in some strange way that can be deleted. I have tried fixing permissions many times. I really appreciate any one who can help me fix the one and only issue that has truly sullied my otherwise perfect Mac experience.