If you want to check upon a service in irregular intervals and decide to restart it if it's not running, then you can use NirSoft's ServiWin. Run it when you need to do a check, and restart the service that was stopped or paused.
If you need a service (or application) to stay up and running 99.99% of the time, then use KeepUpApp. It will (re)start the service or application, and optionally un-pause a service that gets paused, if you set the corresponding checkbox.
KeepUpApp is not for beginners or computer-illiterates, they usually won't need the functions provided by KeepUpApp.