On a computer running Windows NT Server, users who do not belong to the Administrators group also do not, by default, have the Log on Locally user right. In the case of FTP or WWW basic authentication, Internet Information Server attempts by default to log the user on as a local user. With Internet Information Server 2.0 or later, you can change the default logon method by changing the Registry setting, unless the Windows NT Challenge / Response option is checked in the Service Properties dialog box. (Although you should change system configuration by using administrative tools whenever you can, some logon mode settings can be changed only by modifying Registry values.)
Warning
To add or modify a Registry value entry, use administrative tools such as Control Panel or System Policy Editor whenever possible. Using a Registry editor (Regedit or Regedt32) to change a value can have unforeseen effects, including changes that can prevent you from starting your system.