A service that a Windows computer user needs failed to start, according to an error message. What are the TWO locations where that user goes to launch the service?

The Services console (services.msc) contains all services. A subset of those can be found on the Task Manager's Services tab. If the required service isn't there, a link at the bottom of the page will take you to the full list of services. Device Manager is designed for managing hardware and drivers, whereas Computer Management does not have a link to the Services console.