To change the status of a Windows Vista Service, just right click on the service, then choose Properties to get properties window of a service.

Service Window

There are four startup options to check / change they are, Automatic(Delayed Start), Automatic, Manual, Disabled. Some service gets started automatically, others have to be manually started based on the requirements.

Properties Window

User can "Stop" or "Start" a service which has any of the above startup types.

Before changing the properties of the services make sure that it will not affect the windows operating system. So understand and check the service before making even a simple change to the properties of services.