You can install IIS from the Control Panel, but you might need a Windows operating system CD.
On Windows XP, select Add and Remove Programs from the Control Panel, then click Add/Remove Windows Components, select the Internet Information Services check box, and click Next. You can then follow instructions to install IIS. On Vista and Windows 7, go to the Programs and Features page in the Control Panel, select Turn Windows features on or off, and select Internet Information Services.
If IIS 5.0 or later is installed after the .NET Framework, you must register IIS with ASP.NET manually or reinstall the .NET Framework. To manually register IIS with ASP.NET, go to the .NET Framework path, run aspnet_regiis.exe -i in the command line console, and restart IIS.