I have tried to reload SOUND FORGE Audio Studio 9.0b, from the original CD on a new PC; operating Windows 10. However the program will not let me activate the application. The activation dialog box tells me that the serial number is invalid, even though it was automatically filled out from the CD
Welcome to the Magix Sound Forge users community @Martin-Cole.
Try downloading the Sound Forge Audio Studio 9 version from the Magix Download Center or from My Products in the Magix Service Center. In either case, you likely will have to use the original email address that was used when it was originally registered with Sony to log-in. As I recall, AS-9 was only included with some Sony turntables and has a history of activation problems, This issue has been queried here before a few times and I do not recall any resolution.
You can also try downloading AS-9d from the SCS archives, but the same activation issue may exist.
Magix does not officially support the old Sony versions.. but you can 'try' requesting support.
You best bet would be upgrading to Sound Forge Audio Studio 16. If you have the SFAS-9 serial code you should get the upgrade discount.