Hi Dave
Thanks so much for your reply.
Before I has to change my computer a few days ago (I was using Windows 10 and I'm still on Windows 10), I used a simpler method for screen shots which worked perfectly for me: Alt+Print screen and then I pasted the image on a Word document.
This solution does not work any longer and I don't understand the reason why and I would like to find the way to use it again.
If anybody knows how to, I would greatly appreciate their assistance.