I have two monitors in my computer, but I can get only one to work properly in Ubuntu 19.04.
My video card is an NVIDIA GK107 NVS 510, and I'm using the
nvidia-driver-435 (also tried X.Org X Server but no luck).
xrandr gives me:
xrandr: Failed to get size of gamma for output default Screen 0: minimum 1920 x 1080, current 1920 x 1080, maximum 1920 x 1080 default connected primary 1920x1080+0+0 0mm x 0mm 1920x1080 77.00*
lspci | grep VGA gives me:
03:00.0 VGA compatible controller: NVIDIA Corporation GK107 [NVS 510] (rev a1)
I also tried purging
nvidia-* and re-selecting
nvidia-driver-435 under Additional Drivers in Software & Updates.
If it helps, when I open the NVIDIA X Server Settings program I don't actually see anything (apart from the quit and help buttons - I tried reinstalling this as well).