How to run the schedule job when the user is in logoff

Hi
I am successfully created the schedule for the process and running, but some issues are happening ,

  1. It could not run the process while the system had logged off. How to run the schedule job when the user system is in logoff.
  2. I cannot stop the robot job even i used the Delete task activity.

Kindly give me any solutions to resolve these issues .I could not know how to resolve these issues.

Thanks
@PraveenKumar_S