@Edward-Foster Go to Magix.com. Log into your user account with your e-mail address and password and download the Sound Forge installation program under 'My Products'
As @SP. stated, log into the Magix Service Center> My Products. Use the email address that was orignally used when it was registered with Magix or SCS (Sony). In any case, serial code and email address are paired. Alternately, download SFP-11 from the Magix Download Center.