Unable to log in after updating

I have update the 14.04.01 to 14.04.02 and now I am not able to log in in the GUI using my account (only guest session GUI is available) - I am not getting any errors, just a short black screen flash.

I have opened the terminal, log with my account and perform the following commands (I have found them as being solutions in similar questions) but nothing changed:

sudo chmod -R ug+rwx /home/gotqn
sudo reboot

and

sudo rm /home/gotqn/. Xauthority*
sudo apt-get install --reinstall xorg
sudo reboot

and

chown -R gotqn:gotqn /home/gotqn
sudo reboot

and

sudo apt-get-install ubuntu-session //it was the latest version
sudo reboot

Could you advice what to try?