When purchasing the Platinum Suite, your Nero Account is automatically created based on the email address you entered during online purchase.
Once your order is complete, you will receive product information email with your password which is an 8 bit code, like this:
In Nero Start, please enter the email address you entered during purchase, and the 8 bit code you received in the email to login. When login successful, your software is unlocked automatically and could start to run. You don't need to enter serial number anymore.