Enter console
Ctrl+Alt+F1
Complete your update and reboot your system
sudo dpkg --configure -a
If the above gives errors of broken packages, execute below command
sudo apt-get install -f
sudo dpkg --force-all -P pkgName
sudo dpkg --force-all -P linux-image-extra-3.xxxxxxx-generic
sudo apt-get autoremove
sudo apt-get autoremove --purge