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I've updated Ubuntu few days ago to Ubuntu version 12.04.3 LTS (GNU/LINUX 3.2.0-58-generic-pae i686) and now i get stuck with a full screen terminal right after de loading screen.
Identifying the problem
As this answer suggested
startx prompted many informations among wich :
NVIDIA: API mismatch: the NVIDIA kernel module has version 304.88, but this NVIDIA driver component has version 304.108.
So it seems that getting the right driver version would solve my problem
Solving the problem
Followed these instructions :
remove nvidia related stuff with
sudo apt-get purge nvidia* then restart machine with
sudo shutdown -r now