Windows problem

If you have a prior reset point; then use it.

Hopefully you use some top quality virus detector because that sounds sort of like some sort of 'playful' infection that idiots create. If not buy one and scan the PC.

Personally I use a full AVG package and a custom built VPN ... But you can buy a VPN such as Nord which is very good and it all makes it much harder for people to mess about with your pc.

Personally I have no silver bullet for you. Maybe someone else does.

I haven't thought it might be some virus, so thanks very much!

It may be a setting. Check your preferences

Read this article, look at option five about how to check the settings.

https://www.tenforums.com/tutorials/66634-open-each-folder-same-new-window-windows-10-a.html

Accordingly, it still mustn't be a virus. Yes, this link is really about my problem, so thank you very much! I'm trying to do as written, however presently I'm failing to do so. The whole thing begins with "Open File Explorer (Win+X)." So must I have a "Win" button? Could you tell me please?

Oh, I idiot. Thanks again very much!

For curiosity's sake, what in the heck do you mean you cannot afford to close them? Closing a window doesn't delete the contents of the window. Or...?

I just mean that I must do something which is normally not my task, it happens automatically. It has become annoying that I must always do an additional thing, which doesn't seems to be a great thing, closing a window, yes, but too much little things makes one big thing, which is the fact that it continually disturbs my concentration while doing my works on the PC.