I have Ubuntu 16.04 running. It was working fine until I tried to load Windows onto a partition. I had to quit because I needed to format one of my drives which I had some important files on. When I switched back to ubuntu, my screen resolution was set to 4:3 instead of 16:9 and when I clicked 'display' I could not set it back, as 4:3 was the only option available. How do I revert back to 16:9?
Also, when I run
sudo xrandr -q, I get the following error:
xrandr: Failed to get size of gamma for output default