If you are reinstalling on the same computer, it should have kept the serial number in the registry, so it should be already available in the "help" "About Magix" after you finish the reinstall.

If this is not so, and you don't have the email from Magix, then I suggest you contact Magix support at support.magix.net ("contact" is an option on the left).  Email them and explain what happened.  You should email from the email account you used when you registered to avoid any confusion.  Magix knows their customers by their email addresses.


Hope this helps.