Common

If at any point you mess up big time (like completely removing network manager and drivers)

• Restart
• Before booting into ubuntu start pressing shift (or escape if UEFI)
• This will bring up the GRUB
• Go to advanced and select the older/oldest kernel
• It should boot just fine in a mostly working state
• sudo apt-get update
• sudo apt-get dist-upgrade
• sudo apt-get install --reinstall linux-image-extra-virtual
• sudo ubuntu-drivers autoinstall