How to install theme:

1.Download Universal Theme Patcher from this address: 
http://deepxw.blogspot.com/2008/11/universal-theme-patcher.html 
follow instructions from zip file and patch your system.
-Skip this step if you already have patched system.
2.Copy theme files and corresponding folder from "Windows 8 Themes\Windows 8 RTM Grey\Windows 8 Main Theme" folder to "C:\Windows\Resources\Themes" folder.
3.Apply from personalize or double click on the theme file.

Enjoy in theme!!!