Run Service Before User Login?

I am using Windows 7 and this is my situation. I have a desktop connected to an interactive whiteboard used for teaching. My problem is that the board doesn't work until a user logs into the system. The board's operation is controlled by a system service which starts on user login. What I want to do is to start the service at Windows startup BEFORE login so that the board is activated and I won't have to use a mouse just to click on a users account. I tried, opening services.msc but it startup was already set as AUTO. I also tried creating a batch file with the command SC start <serviceName> and add it in the registry, in HKLM/Software/Microsoft/WIndows/CurrentVersion/Run but all these only executed after user login. After many hours of searching in the net, I fould 2 more ways, through task scheduler and local group policy editor as a startup script (Haven't tried them yet)....However I am almost sure that a service can run before windows login, because other Software, for example Teamviewer, when you enable start with Windows, it is activated before login. The teamviewer service has the same settings with my classboard service. I even used a registry monitoring software to find out what teamviewer changes when starting with windows is enabled, and the only thing that changes is a registry key in Teamviewer settings about autostart and always on, which are irrelevant to the system sevices as far as I can tell....