Other than directly running and applying the regional theme in order to unhide and reveal the hidden themes in Windows 7, it’s also possible to directly modify the registry in order to enable and turn on these regional themes and wallpapers for selection in Windows 7 Personalization and Desktop Background.

After downloading and unpacking more Windows 7 regional themes and wallpapers, such as specific theme and wallpapers for Japan and German market, use the following registry hack to automatically and instantly unhide and reveal all these themes and wallpapers for use in Windows 7 Control Panel -> Personalization and Appearance configuration (shortcut is right click on desktop and choose Personalize).

Download win7-enable-regional.zip

Extract the ZIP file, and then double click on the win7-enable-regional.reg to apply and merge the registry entries to system registry to enable and turn the Windows 7 regional themes and wallpapers.

Alternatively, copy and paste the following text in Notepad or other text editor, and save the file with a name with extension of .reg. Run the file to install the regional themes and wallpapers.

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Themes\InstalledThemes\MCT]
"%windir%\\Globalization\\MCT\\MCT-AU\\Theme\\AU.theme"=""
"%windir%\\Globalization\\MCT\\MCT-CA\\Theme\\CA.theme"=""
"%windir%\\Globalization\\MCT\\MCT-DE\\Theme\\DE.theme"=""
"%windir%\\Globalization\\MCT\\MCT-GB\\Theme\\GB.theme"=""
"%windir%\\Globalization\\MCT\\MCT-JP\\Theme\\JP.theme"=""
"%windir%\\Globalization\\MCT\\MCT-US\\Theme\\US.theme"=""
"%windir%\\Globalization\\MCT\\MCT-ZA\\Theme\\ZA.theme"=""

[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Wallpapers\0\KnownFolders\Windows Wallpapers\MergeFolders]
"%windir%\\Globalization\\MCT\\MCT-AU\\Wallpaper"=""
"%windir%\\Globalization\\MCT\\MCT-CA\\Wallpaper"=""
"%windir%\\Globalization\\MCT\\MCT-DE\\Wallpaper"=""
"%windir%\\Globalization\\MCT\\MCT-GB\\Wallpaper"=""
"%windir%\\Globalization\\MCT\\MCT-JP\\Wallpaper"=""
"%windir%\\Globalization\\MCT\\MCT-US\\Wallpaper"=""
"%windir%\\Globalization\\MCT\\MCT-ZA\\Wallpaper"=""

There is now easier and more generic method to unlock, unhide and enable the hidden themes in Windows 7.