Andrew,
You are right, I must correct my fourth point:
4) In the SSD /bb folder I see the files exe, the full and trial tickets and the NNpredictionDispatcher_on.dll. I see also many stx + sty, st2+xt2 files (years 2016/2017). Is it normal ? What can I do with them ?
During cut and paste operations it remained an erroneous bb\data in the message.

I have appreciated your advises A-E) very much.
I still have a lot of things to learn !
THX. Kind regards. Angelo