Office setup adds the Microsoft Word to the HTML Editors list in Internet Explorer options automatically. If that doesn’t happen (Word isn’t listed), this post tells you how to add it back to the HTML Editors list.
To include Microsoft Word to the list, open Regedit.exe and go to:
Create a sub key named winword.exe
Exit the Registry Editor.
Word is now added to the list of HTML Editors, in Internet Options > Programs tab.
Alternately to accomplish this using command-line, open a elevated Command Prompt and type this command:
REG ADD HKEY_CLASSES_ROOT\.htm\OpenWithList\winword.exe