Nvidia driver issues?

Hi there,

Today I wanted to upgrade from Ubuntu GNOME 15.10 to 16.04 LTS. The upgrade was done, the system started properly (apart from several apps missing that was caused by the upgrade, but that's the least disturbing part), however, when I switched to proprietary, "TESTED" NVidia driver and restarted my system, a black screen greeted me.

After the boot screen, the screen just shuts down and nothing happens. So I tried to install Ubuntu 14.04.3 LTS, which is working properly with NVidia drivers.

The only error message I got was when I tried to install 16.04 again, then something like "nouveau: unknown chipset" appeared for a brief moment, but literally just a split second, then the installation began.

I have an NVidia 840M card in my laptop and everything worked fine with 15.10.