Hello, sorry for my delays, but as I told you before, i'm quite busy since the beginning of this year.
What I did : I tried the DISM to reinstall DotNet, unsuccessfully.
As I needed to have an operational computer everyday (For my second business), I decided to buy a new SSD drive. A larger one, 500Gb instead of 256, it took some time, I received it last week.
And the fun began there: I restored the image I did before my first contact with you.
Booted on it, with it's original default. At this time Dotnet seemed to work, everything (except the updates) seemed to work.
I tried on this version the DISM, still unsuccessfully.
So I decided to apply the solution to reset the system. It didn't work.
After booting on a restoration CD, I tried the same, nope ...
Finally, I had to format the system partition on the new device to reinstall from scratch the windows 10 (the 1909 version), and of course to rebuild completely the system and applications. It worked !
Now I'm at the stage of restoring the settings and datas of my profile, but everything works basically.
At the first part of all this process, I was thinking of a SSD default, but after restoring the partition on a new device, it can't be that.
Furthermore, tests with different utilities showed no particular default, neither in the smart datas, nor in the "surface" tests.
At this point, and only for my own curiosity, I wonder if the problem was not a problem of loss of credentials on some system directories, blocking the system from it's modifications.
If you've got an idea, you're welcome !
Anyway, I wanted to thank you from your intervention, your involvment, and the time you spent on my case.
A least, with your help, I learnt some new things about the windows updating process.
Thank you
Sincerely
Olivier Kerr