Hi Curson,
Thank you very much for your answer.
I use Windows 10 Family version 1709; I think I missed only the last two major updates, in march and october 2018.
I have solved rather mysteriously the problem of the main window blockade by these actions: close the "empty window " (of detections) by clicking on the cross on it; close the main window by clicking on the task bar; open it again by clicking on the task bar. After this it was unblocked. But the first time I made this, I was notified that my version, the 12.13.4.0, was obsolete; I got the 12.13.5.0 and made the scan again, this time in only 4 hours; rather mysteriously my computer works better than one or two days ago. This new scan found 106 problems instead of 105.
So now I face a "classic" problem: choose the files to remove. I have one red, three grey, one orange which turned in green, and the rest in orange; they concern mostly users or minor softwares and not the system itself, so I am tempted to remove everything except the green.
What is the usage for the beginners: try to do oneself if it seems not too dangerous, or get advice to learn? Is it useful to open a topic, and where?
For the V13 Beta version I am about to inform me. What is the difference?
Thanks again for your welcome and answer.