Stangely, the exact same symptoms have been happening for me after the
upgrade from 12.04 to 13.04. Once in a while the same thing: new Firefox
tab, loads for a second, and Gnome/X freezes. Mouse cursor moves, and
processes seem to keep running.
I can still SSH into the box. Killing processes
** Attachment added: Dependencies.txt
http://launchpadlibrarian.net/36367746/Dependencies.txt
** Attachment added: ExtensionSummary.txt
http://launchpadlibrarian.net/36367747/ExtensionSummary.txt
** Attachment added: XsessionErrors.txt
