This security setting determines which user accounts can call the CreateProcessAsUser() application programming interface (API) so that one service can start another. An example of a process that uses this user right is Task Scheduler. For information about Task Scheduler, see Task Scheduler overview.
Computer Configuration\Windows Settings\Local Policies\User Rights Assignment
Network Service, Local Service.
At least Windows XP SP2, Windows Server 2003
User Rights security settings are not registry keys