Hi Gary,
You may try to create script task with command like:
tasklist /FI "IMAGENAME eq notepad.exe" | find /I "notepad.exe" > nul
Such task should return success if notepad.exe is running and should fail if notepad is not running.
Then add that task to the MSD policy "Dependency Tasks". MSD should fail with "Not Compliant" status if notepad.exe process is not active.
Thank you,
Alex.