You should be able to use "Reliability and Performance Monitor" tool to run a specific command line (Send a Trap) if a process does not exist, which is what happens if a service is stopped. (Process count is below 1)
In Reliability and Performance, open "Data Collector Sets" and create a new "User Defined" set and choose "Performance Counter Alert", then add "Process" -> "Thread Count" and choose your process name and finish. Then go to the properties of the newly created DataCollector and chose the "Task" tab and add the command line you want.
Vahid
