On Linux, they are all read only, so no problem.

But on MS Windows, what happens is like this: I get curious about the definition of the command isearch-forward, I type C-h f isearch-forward and click on the link isearch.el from the help to get to the definition of the function, and while I am reading its definition, I press C-h or C-c many times, but I set Caps Lock as another Ctrl key, so sometimes it happens that I release Caps Lock too early, in which case C-h or C-c becomes inserting h or c, sometimes I notice that and undo it, but sometimes I don't notice it, and I even save them all with C-x s.

What is a good way to protect the built-in el files from me on MS Windows?