Jürgen, this bug report is being closed due to your last comment
regarding this being fixed by a configuration change. For future
reference you can manage the status of your own bugs by clicking on the
current status in the yellow line and then choosing a new status in the
revealed drop down box.
The problem could be solved.
The steps described in various tutorials (remove all existing nvidia-
packages, install headers etc.) didn't help even reinstalling.
I realized that copying my system to a new disk (ssd :-) ) was
uncomplete. After fixing that everything worked again.
I don't now
