If objService("StartMode").ToString = "Automatic" Then
You are using late binding, a way to use COM objects that tends to slap you with runtime errors when you use their properties and methods incorrectly. You can avoid these kind of problems by using the classes in the System.Management namespace.
The statement doesn't do what you think it does, it calls the default property of the interface and passes "StartMode" as an argument to the property getter for that default property. That's not correct usage of that interface, StartMode is a property by itself and it is not the default property. Fix:
If objService.StartMode = "Automatic" Then