Which version of Sound Forge?. Read the 'Sticky' at the head for the main Sound Forge forum page.

Log into Magix Service Center and select "My Products" to find your product's activation serial code and download the product. You will need to log-in using the email address and password that was used when your version of SF was initially registered and activated. If you do not have the log-in info, email Magix Customer Service: infoservice@magix.net.

btw, seasons greetings and welcome to the Magix Sound Forge users community @Comunicao-secomrs.