In case IIS is installed after the .NET framework based on MSDN

"%windir%\Microsoft.NET\Framework\version\aspnet_regiis.exe" -i

also works for the latest Framework versions…

“After you install the Microsoft .NET Framework Software Development Kit (SDK), Microsoft Visual Studio .NET 2002, Visual Studio .NET 2003, or Visual Studio 2005, Microsoft Internet Information Service (IIS) mappings are created to associate the new file extensions and settings for ASP.NET. If you did not have IIS installed when you ran the SDK or Visual Studio Setup, or if you uninstalled and reinstalled IIS after you ran the SDK or Visual Studio Setup, those settings will not be in place. You experience unexpected behavior when you try to view ASP.NET pages.”