Comment 6 for bug 559930

This is occuring to me since I upgraded to 12.10 beta 1. I thought that it was a problem with the graphics drivers related to having nvidia optimus.

How to log in:
When I notice that the mouse button gets changed to an arrow and the login screen isn't shown for one to two seconds (after this time the mouse and keyboard stop responding so this has to be done before that happens) I press alt + ctrl +f1 and log in with my user.
Then I restart the gdm with sudo /etc/init.d/gdm restart and the login screen shows up so you can log in normally.

I'm using gnome-shell and gdm.