You likely used a different log-in (email address) when you initially registered/activated Vegas and Sound Forge. Your products' registered (log-in) email address should be stated in the "Help> About "menu: "This product is registered to:"
Your log-in for the forums can be different.
If you can not access your "My Products" list, email Magix customer service: infoservice@magix.net 

rraud, Magix forums moderator