If I was to downgrade from Windows 10 to Windows 8, will I be able to re-install windows 10 at a later stage at no cost?

Ok Friend. Thanks for your advice. And I also find the solution for this.

I am going the boot the windows 10 again. So that Installed Software only removed. We can get back Desktop Files(C Disk files).

And another file will not deleted.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.