Did you receive the error message “This theme can’t be applied to the desktop!” after applying an unsigned 3rd-party theme? If you did, read this tutorial and learn how to fix it and how to install Windows 7 themes properly.
Windows 7 does not come with built-in support for 3rd-party themes, that’s why you have to patch some dll files first in order to apply the themes.
If you did not patch your files properly you will always receive the error message: “This theme can’t be applied to the desktop!”
The following tutorial you will teach you everything about installing 3rd-party themes. I highly recommend Method 2: UXTheme Patcher, because it’s the easiest one and you can’t mess up much:
So, apply the patches. Next, copy the 3rd-party themes to C:/Windows/Resources/Themes, then you can simply double-click on them and the theme will applied to the desktop!
After you have patched all files successfully AND restarted your PC you will no longer receive the message “This theme can’t be applied to the desktop”.