Comment 3 for bug 367365

Hi Mario, please select the top most recovery option in GRUB and when you arrive at the recovery menu (text mode with blue background) please select "netroot". From there, run the command "sudo apt-get install ssh".

Then you reboot and you try to start the machine as usually, when the machine hangs connect to it using ssh from another computer and then run this command:
apport-collect 367365

Doing so will provide us with detailed info about your sw/hw config plus also log files (xorg log full dmesg etc) that might show traces from the freeze etc.

Also inspect /var/log/gdm/* and see if there is any interesting errors in there. Thanks.