Process checker / program launcher

I have some Windows NT systems with a homegrown application that we need to make sure is running at all times. The program cannot be installed as a service, as it will not work properly. What I am looking for is a program/service/script I can use that can check to see if program xyz.exe is running. Have it check every 15 minutes or so. If the program is running, everything will be good. If program xyz.exe is not running, I need to it launch it before it goes back to sleep.