You might want to have the server always running, no matter who is logged in to Windows. This is possible by using the NT Service version of WWW.
To start using it, just go to the command line and type:
www_ntservice -install net start www
This will install the service and start it.
To change the configuration of the NT service, you can use the GUI application. Any change you make with the latter, will immediately and automatically be taken over by the service.
The NT Service registers whether it is running or not, so that the GUI can adjust to that fact. However, a crash of the service might occur. In that case, it will not unregister itself so that you cannot use the GUI server normally. To solve this, either start and stop the NT Service, or click the blue link in the GUI main window for a forced reset of this registration.