After successfully installing Ubuntu and logging in to the Unity desktop, I followed the prompts to enable the proprietary display drivers.
After rebooting, the Unity desktop is now entirely unresponsive. The mouse pointer moves but I can't do anything.
After some research, it looks like it is specifically a problem with these drivers and Unity, so I should be OK with, say, the classic Gnome desktop.
Unfortunately, I enabled auto login so I don't get the chance to chose another desktop. Can I fix this from the CLI?