I had my system working pretty good with the external monitor working with the displayport. Unfortunately I felt that I should try to install Bumblebee. It didn't work. The monitor wasn't recognised. So I uninstalled it with the instructions on ubuntus wiki. But it didn't get back to the way it was. And when I copied the Purge-command it started deleting other stuff to, like Cheese and whatnot. I can't get the external monitor to be recognised. If I activate Optimus I get the right settings on my laptopscreen, but no Nvidia-drivers. If I deactivate optimus I get poor resolution on my laptopscreen, and still don't recognise the external monitor. But the Nvidia-drivers show up and can be activated. Why oh why did I have to try to install Bumblebee.