OS X Boots Back Up with All Default Configurations

[dooododoo]

I got my osx86 (jas 10.4.6) set up with 1920x1600 resoultion, qe/ci, touchpad, etc, etc to all work. So I set up all my preferences, input in iCal events, downloaded some programs, put and organzied my programs in the dock, etc.

 

I turned off my laptop off at night and then in the morning when I turned it back on, every setting was deleted. My iCal appointment were all gone. My iTunes library was cleared (although my mp3s were in the correct folders). All my preferences in the Preferences were reverted to default. My Dock was reverted to default. Basically all my customization was reverted to default, although my files such as mp3s, programs were still installed.

 

Has this happened to anybody? CAn someone explain why this happened? What can i do to prevent this from happening again? Anything to help explain this would be greatly appreciated.