I tried to install Emacs and AUCtex on Windows 8.1 without success (at least, it does not seem to work to me). With the risk of being pedantic, here are the steps I followed:
1) Extracted the most updates emacs zip folder in c:/Program Files(x86)/Emacs/emacs-24.4
(emacs per se seems to work. If I open a .tex file, in the menu appears "TeX", I can compile with pdftex using C-c C-c , etc.)
2) Extracted the AUCtex zip folder in the same location.
Now, if I open a .tex file with emacs, nothing has changed with respect to the previous situation.
Do I miss some steps?