What you purchased was Media Jukebox 8. You have up to 10 restores a year available for that, in case you lose your license for some reason.
Since we made Media Jukebox 8, there's been Media Center 9, Media Center 10, Media Center 11, and Media Center 12. Each one is a new product and requires a new purchase of a license. We do have upgrade pricing for customers who have purchased previous versions.
If you want to switch from using Media Jukebox 8 to Media Center 12, you will need to purchase a new license. Or you can continue to use MJ8.
Hope this helps...
j