Ok, first of all, when you hit Ctrl+Alt+F1 to have access to another terminal, I believe you're trying to type a command that doesn't exist simply because Nvidia drivers are not installed yet (that's why the output message is «command not found».
So my advice here is to type
sudo dpkg-reconfigure xserver-xorg
you'll be guided to several steps where you can reconfigure your keyboard, mouse, display driver and screen resolution.
My suggestion is to go through those steps and, if your keyboard and mouse are correctly set, just don't change them, just leave them as they are.
With the display driver you should look for one called «nv» or, if you don't see it, just pick the one called «vesa», it usually works for any display and for me, it's the one that get's me out of trouble
After that you can choose what you'll find to be the correct screen resolution.
When all this is done just logout (you don't have to restart, I think!) and hit Ctrl+Alt+F7 to return to the GUI interface (not terminal).
Hopefully you can manage the installation of the correct driver for your graphics card within Ubuntu GUI.