You could use the Services MMC to to uncheck the Allow Service to Interact with Desktop check box on every service, but it is easier to use Regedt32 to navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Windows and set the NoInteractiveServices value name, a REG_DWORD data type, to 1.

NOTE: The NoInteractiveServices value name was designed to improve performance of unattended computers.

NOTE: The NoInteractiveServices value name will not prevent a service from issuing an error message.