Retrieve through the registry.
1. First turn on the computer and click "Run" in the start menu bar in the lower left corner.
2. Then click and enter "regedit" in the pop-up window and press Enter to confirm.
3. Then find the SoftwareProtectionPlatform item in WindowsNT/CurrentVersion in the pop-up window.
4. Then find the key value of "BackupProductKeyDefault" in the pop-up right window, followed by the "Activation Key". The trademark digital certificate activation code is automatically generated by the system, and this activation code must be used to activate the trademark digital certificate.