I've been using Ubuntu 12.04 for close to a year. Occasionally after booting into Gnome 3, the desktop is unresponsive to cursor clicks. The mouse cursor moves but can't open menus. Also the network icon displays a red error badge instead of the usual gray x indicating that it is off. The only way I have found to solve this is to switch to a terminal shell (Ctrl-Alt-F5), login and kill gnome-session. This is an intermittent and occasional problem.

Recently I moved house and set up this computer in my new apartment. Now I have for the first time a new and more difficult problem. Switching on the wireless card (wlan0) to connect to the wifi router causes the desktop to freeze. Switching to a terminal via Ctrl-Alt-F5 doesn't work. The only solution is a hard reboot from the power switch.

How can I diagnose the second, more recent problem? Is there a solution?

Cheers,

Ryan