Booted laptop. At the prompt I did: $ xset s off ... Got error: xset: unable to open display " "I then started X and opened a terminal window. I did $ xset s off and did not get an error, it just put back at the prompt. X still aborted. I rebooted my laptop and tried again.... still aborted. I have noticed that it crashes at about 20 minutes after being left idle. This does not happen with my PC, only the laptop.