Some themes you can unlock yourself! The Window 7 operating system has
some hidden & locked themes that were created for countries all over
the world(Canada, Great Britain, United States and South Africa).
Actually it’s pretty easy to unlock them.
1. Simply open the Explorer (Windows + E) and go to C:\Windows\winsxs
2. Enter *.theme into the search field.
3. Double-click the themes ZA, US, GB, CA, AU to install them.
4. you have unlocked 5 cool themes.