Did you know that Windows 7 has hidden themes for different regions like Australia, Canada, Great Britain, United States and South Africa?Here is simple windows 7 tweak, which will show you how to unlock windows 7 hidden themes
1) Go to windows Explorer

2)Click on Organize -> Folder and Search Options


3) In Folder options click on View tab and select Show hidden files, folders and drivers and uncheck Hide protected operating system files (Recommended). If prompted with confirmation, click Yes.

4)Browse to \Windows\Globalization\MCT\ (just type \Windows\Globalization\MCT\ in windows 7 search field ) . There are five folders in the name with format MCT-XX . Go into the folder that you want to activate its theme and double click on the XX.theme file to apply the theme to the Windows 7 desktop system. Once a theme is ran and activated, the theme will be remembered and saved into Personalization options