Most WWW servers on Windows NT are implemented as services. A special Services applet on the Control Panel is used to start, stop, or pause a service. Services don't act with the authority of the logged-in user. That means that services can't see user environment variables or read files that are readable only by the logged-in user. You can set the account that a service uses in the Services applet on the Control Panel.
Services run even when no one is logged in to the machine.
The most important thing to remember is that you have to take special steps to make resources available to services. Win32 platforms don't have the same mechanisms for setting permissions on files as UNIX does. All files are available to all users. For files on an NTFS partition on Windows NT, you can set the security permissions on a file using the Explorer and the properties sheet of the file. Select the Security tab, and press the Permissions button to set the Permissions on the file.