Windows does not allow you to install 3rd party themes. You have to patch some system files to be able to do so. This new version 1.1 will automatically patch the system files without the need of a 3rd party system file patcher. If the system files are already patched then it does nothing. To restore the patched files you will need to use Universal Theme Patcher or UxStyle Core.

How to use Windows Themes Installer:

INSTALL A THEME AND CHANGE SYSTEM FILES:
1. Run the tool as Administrator.
2. Select the options which you want to install:
i) Theme
ii) Explorer.exe
iii) OobeFldr.dll
iv) ExplorerFrame.dll
v) Shell32.dll
3. Once you have selected the options, click on the “Browse” button and browse for the file of the desired option.
4. Now click on “Install Theme” button to install the theme and replace the system files.

RESTORE DEFAULT SYSTEM FILES:
To restore the default system files click on the “Restore Default System Files” button.

REMOVE A THEME:
To remove a theme select the theme which you want to remove from the list and click on the “Remove Theme” button.

APPLY A THEME:
To apply a theme select the theme which you want to apply from the list and click on the “Apply Theme” button.

It is always a good idea to create a system restore point first before making any changes to your system. Should the need arise, the System File Checker Utility will help you replace your system files with ‘good original’ Windows system files.

http://www.thewindowsclub.com/windows-themes-installer-install-windows-7-vista-themes-easily

A Guy