How to get relative linking pointing to the right folder

I have a website at example.com/folder. I have been using relative linking all along (i.e. use a href="/about.html" instead of "http://example.com/folder/about.html")

Now, for this folder, the link is set to "/about.html" and it points to example.com/about.html instead of example.com/folder/about.html.

Assuming I cannot change the hyperlinks of all these links in several thousands of pages to the right link, is there some way out?

Also, could someone tell me if changing the relative links from"/about.html" to "./about.html" will help?

 

Tried "../about.html" ?

 

From root : http: //example.com/

to : "folder/about.html"

and back to root : "../folder/about.html"