If you absolutely need the official software, write down your Hardware ID (found in the activation screen) and email with proof of purchase. Expect to pay for a replacement key.
Have a working key for a legacy version? Share the format pattern (not the actual key) in the comments to help others identify if their sticker is valid for 9.0 Deluxe or a different version.
The VidBox hardware is durable and useful. The VHS to DVD 9.0 Deluxe software is abandonware. Do not waste hours hunting for a product key when modern free tools work better.