Navigate to the Emacs download section, and click the mirror link:
Download the latest Emacs .zip file:
Extract the .zip file
Copy the folder to c:/Program Files. If you want, rename the folder to emacs (this is optional).
Open the bin folder, and start runemacs.exe:
An Emacs window should appear:
You can also optionally add the bin path to your system path so you can type "emacs" from a command prompt to open Emacs. If needed, here's an example of how to add a path to your system path.