Alternatively, you can just extract the contents of deskthemepack/themepack. Tip: See how to install a Windows 8/Windows 10 theme in Windows 7 using the Deskthemepack Installer freeware. The file contents of the deskthemepack file are identical to the themepack file, but the *.theme format is slightly updated to include additional information and can't be directly installed in Windows 7. Windows 8, Windows 8.1 and Windows 10 are using a new format, *.deskthemepack. Windows 7 used the '*.themepack' file extension.

As you might be knowing, Windows 7 was the first version of the operating system which got support for themes. Technically, these are still regular *.deskthemepack files. Seven new themes found their way to the Store and were available for free. Today, the first set of themes became available in the Windows Store. This indicated that Microsoft was going to sell themes using the Store. There was no official announcement about themes, however, a screenshot of Windows Store was shown with both free and paid themes.

The ability to install themes in Windows Store was demoed during the October 2016 Microsoft event.