[ubuntu] problem to start ubuntu after upgrade to 16.04

Hello,

I need some help. I upgraded from ubuntu 15.10 to 16.40, and now ubuntu does not start properly. When I choose ubuntu in the grub-menu (?) (I have dual boot with windows 10), the screen goes off, the keybord goes off and nothing happens. (windows still starts properly.)

Now I am in recovery mode, which runs properly.

I have no professional knowledge of computer systems and do not know what to do.
Which data would be needed to get a better picture?
I uploaded a boot-repair info: http://paste2.org/cOIVf64W. However, it does tell me nothing...

Tonio