Well,
Since I got no answer, I aborted the stuck installation. Then tried to reboot the computer, to my surprise it started with alphanumeric ttys (6 of them) on 16.04.1.
I started to work on it, tried to burn a DVD, some library was missing for 'brasero'. I started to install following hints that I got from the system, and finally after some commands, that I list below, the system asked for reboot. Following the reboot I have a full functioning 16.04.1 (at least so it seems now).
The commands I typed following hints from the system:
$ sudo apt-get install brasero
$ sudo dpkg --configure -a
Then again, I tried
$ sudo apt-get install brasero
$ sudo apt-get -f install
$ sudo apt autoremove
$ sudo apt upgrade
$ sudo reboot
If more explanation is needed, I'll be glad to try and provide it.
Regards.