MacBook randomly logging out (with video)

[xwinger]

so I opened up my macbook this morning (late 2008 aluminum) and it was at the log in screen which was weird so i logged on and came to discover that when i click on the applications folder in the dock that opens up the grid view, it logs me out. any suggestions?

heres a video

http://www.youtube.com/watch?v=VVFvVXkhvAY

 

[eman]

Have you repaired permissions with disk utility? I've never experienced this problem before, you may have to reload the OS (archive and install).