Try entering TTY or Terminal with ctl+alt+F4 or ctl+alt+F5
(If doing this from the desktop, using ctl+alt+F7 will get you out of TTY)
Run:
sudo apt --fix-broken install
sudo apt update
If using Nvidia:
sudo apt remove --purge '^nvidia-.*'
sudo ubuntu-drivers install
sudo apt clean && sudo apt autoremove
sudo apt full-upgrade
Reboot and test...