How to enable Windows authentication for a Web site, Web application, or Web service
1.Open Internet Information Services (IIS) Manager:
a) If you are using Windows Server 2008 or Windows Server 2008 R2:
On the taskbar, click Start, point to Administrative Tools, and then click Internet Information Services (IIS) Manager.
b)If you are using Windows Vista or Windows 7:
On the taskbar, click Start, and then click Control Panel.
Double-click Administrative Tools, and then double-click Internet Information Services (IIS) Manager.
2)In the Connections pane, expand the server name, expand Sites, and then the site, application, or Web service for which you want to enable Windows authentication.
3) Scroll to the Security section in the Home pane, and then double-click Authentication.
4) In the Authentication pane, select Windows Authentication, and then click Enable in the Actions pane.
5)Click Enable in the Actions panel
6)Click Advanced Settings in the Actions panel
7)When the Advanced Settings dialog box appears, select one of the following options in the Extended Protection drop-down menu:
a)Select Accept if you want to enable extended protection while providing down-level support for clients that do not support extended protection.
b)Select Required if you want to enable extended protection without providing down-level support.
8)Click OK to close the Advanced Settings dialog box.