the weirdest thing

My Mac Pro randomly logs out while I am working. It has happened in FCP, compressor and Photoshop. I am doing something on the computer, then suddenly the screens go blue, then I am returned to the login window. No, I didn't hit shift-apple-Q. I have never seen anything like this. Any ideas???

"Never underestimate a kick to the nuts"
Bas Rutten

Automatically logging out is very strange. My guess would be that your keyboard is defect... Try another keyboard.

Or maybe: Do you have Remote Desktop installed and someone is playing a trick on you?