I'm using a desktop that I got from System76 with an NVIDIA graphics card. Installing the NVIDIA drivers on Ubuntu wasn't simple, so here are the steps that I've gotten to work across multiple installations.
First remove any existing NVIDIA packages:
sudo apt-get remove --purge nvidia* sudo apt-get autoremove
Next blacklist the nouveau driver. Without this step, the driver can re-appear after an update and cause problems. Create the blacklist file:
sudo vi /etc/modprobe.d/blacklist-nouveau.conf
And add the following lines: