Hi,
start your PC in "Recovery Mode" and click on "Network", then run DPKG (Network cable required) and see if that fixes the problem. Reboot using Ctrl + Alt + Del (do not click on "Resume").
If that fails after a reboot, go back into recovery mode, activate network again and then go to "root" and type the following command:
sudo dpkg --configure -a && sudo apt-get update && sudo apt-get install -f
You can type that as one command as above or do the following:
sudo dpkg --configure -a
sudo apt-get update
sudo apt-get install -f
Then reboot again using Ctrl + Alt + Del (do not click on "Resume").
See the update guide for more info:
Hope it helps.