This forum is for discussing Vegas products - of which Movie Studio Suite is not a part.
You should also include:
Where you bought Movie Studio from - MAGIX's website or elsewhere (e.g. Amazon)
Who told you that the serial number is registered to another user/email address
In any event, this and the MAGIX forum are user forums, not avenues to MAGIX support - so other forum members won't have access to your MAGIX information. To contact MAGIX Support, go to the Support link in the header of MAGIX's forum, select your product, scroll down to the bottom of the page and click on the Contact Support link.