On an Asus rog with GT960M graphic card running Lubuntu 15.10, I installed bumblebee (https://wiki.ubuntu.com/Bumblebee) which rebooted fine. Then I updated the nvidia driver by sudo apt-get nvidia-352-updates nvidia-settings Then tried running the recommended sudo optirun nvidia-settings which returned an error so I did the modifications manually. By editing /etc/bumblebee/bumblebee.conf
Then I reboot. And It doesn't reboot. There is an unusual line : "error parsing subspace pcc from pcct"
Then I can see splash screen, then I can see a login prompt in which I can login : I tried to restart lightdm (sudo service lightdm start) but it fails to start (because of too many start attempts).
I tried to purge (reinstall) the nvidia and bumblebee but it didn't work.
I tried recovery modes (which were at first hidden by splash screen it works but doesn't start gui.
I tried to uninstall lightdm and reinstall.
Internet works on the computer, screen works as I can see text and splash screen on startup and shutdown. I can access disk fine and run commands.
I don't know what I can do to get it to get the GUI work again.