Prevent Task Run or End
Computer Configuration\Administrative Templates\Windows Components\Task Scheduler
Prevents users from starting and stopping tasks manually.
This policy removes the Run and End Task items from the context menu that appears when you right-click a task. As a result, users cannot start tasks manually or force tasks to end before they are finished.
This policy appears in the Computer Configuration and User Configuration folders. If both policies are configured, the setting in Computer Configuration takes precedence over the setting in User Configuration.