Comment 4 for bug 374831

Thanks for the info, Tom - it sounds like an X crash.

To determine the extent of the crash:
+ Does ctrl+alt+f1 take you to a console?
+ Does ctrl+alt+backspace restart X?
+ Does mouse pointer still move? [No, it doesn't]
+ Does the keyboard LED come on when hitting the CAPSLOCK key?
+ Can you ssh into the system from another computer? [No ssh, network, pings]

Can you attach the following files?
/var/log/Xorg.0.log
~/.xsession-errors
 and enable Apport as described:
https://wiki.ubuntu.com/X/Backtracing#Apport%20-%20Or%20debugging%20the%20easy%20way

I'm classifying this for xorg-server