In windows 7 by default ISAPI & CGI Restrictions are not configured. To enable ISAPI & CGI restrictions, GoTo -> Control Panel -> Programs -> Click on "Windows features on or off -> Expand Internet Information Services - >Expand World Wide Web Services ->Select CGI and ISAPI extensions and Click OK.
After enabling, Check in IIS, Open your IIS and the feature will be available.
What is ISAPI and CGI restrictions : ISAPI and CGI restrictionsare request handlers that allow dynamic content to execute on a server. These restrictions are either CGI files (.exe) or ISAPI extensions (.dll). You can add custom ISAPI or CGI restrictions if the IIS configuration system allows this.
What is ISAPI and CGI restrictions : ISAPI and CGI restrictionsare request handlers that allow dynamic content to execute on a server. These restrictions are either CGI files (.exe) or ISAPI extensions (.dll). You can add custom ISAPI or CGI restrictions if the IIS configuration system allows this.