I'm running Linux Mint 17.2 KDE (Ubuntu 14.04 LTS), and following a software update my machine no longer recognizes my monitor and I'm stuck at a low resolution. I have an Nvidia GeForce 650 graphics card.
I've tried regenerating xorg.conf with nvidia-xconfig, but that didn't help. The nvidia-settings utility runs but the only options available in its sidebar menu are Application Profiles and nvidia-settings Configuration. In the console, nvidia-settings raises the error "nvidia-settings could not find the registry key file."
The monitor in question is fairly old and connected with to a DVI port with a DVI-VGA adapter, if that provides any clue.