Here you go folks! Just open explorer and go to "C:\Windows\winsxs". Once there type *.theme into the search box in the upper right corner. Scroll down until you see files with a .theme extension, they should be titles like "scenes.theme, aero.theme, etc.  Double click on each .theme file to install it. Heck, there is even a Windows Classic theme, and a few high contrast ugly ones too!  Enjoy!