If you need to have us sent all your registered SilverFast 8 and 6 product serial number, so that you can download the software again, please use this form to request this: 

https://www.silverfast.com/problemreport/en.html?filter=form&sub=quick&topic=lostserial

The request is done automatically by the web server and the info be sent to your given email address within a short time.