On Windows 8 Pro, I'm trying to add Windows Media Center using the **Add features to Windows 8** dialog, but when I enter my product key I get the message `This key won't work. Check it and try again, or try a different key.`

![Add features to Windows 8 error](https://i.stack.imgur.com/LkAvh.png)

I ditched my cable boxes for Cable cards, so I can't watch TV without Windows Media Center.

How can I install it? Do I need to buy a key for it?