While trying to follow links from main Info page (C-h i then RET on the topic) or trying to open any Info file directly (C-u C-h i), I get the following error:
No such node or anchor: Top
I'm using emacs-25.3_1 for Windows. Everything was working fine, I didn't change anything that I think should affect this functionality, then it just stopped working.
Info-directory-list contains a path to valid .info files.
user-error: No such node or anchor: Top
The openwith package was causing the problem. Through process of elimination, discovered (require 'openwith) was causing the problem. Tested several times to ensure. Commented out, restarted (just eval-buffer wasn't enough) and everything is working fine.