You probably only need to do this on the non-Unicode versions of Windows (95, 98 and ME), and even then, various Windows and Internet Explorer updates have made third party software unnecessary in most cases. If you are having trouble displaying text, try defining a fontset with the font for the languages that the third party software handles set to what that software expects (which may not be an appropriate font for that language, but the third party software is intercepting it and using a different font behind the scenes). See Non-latin display.
In addition to defining a fontset with the expected font, you may also need to disable unicode output with:
(setq w32-enable-unicode-output nil)