Please review SAP Note 870871 - 'License key installation' on how to apply the license key.
Please use SAP User 'SAP*' to logon to client 000 to apply the license key.
See this URL link for the default password for SAP* - Protecting Standard Users - SAP NetWeaver Application Server ABAP Security Guide - SAP Library, if the default password has not been changed.
If the default password for SAP* has been changed and cannot be remembered, please review this URL link - Securing User SAP* Against Misuse - Identity Management - SAP Library, on how to trigger the system to create the hard-cored SAP* with the default password.