In order for your dot net web applications to run properly, the .NET Framework must be installed after Microsoft IIS is installed. If this is not the case for your machine, Microsoft provides the aspnet_regiis utility program to un-register and then re-register the .NET Framework. Its purpose is to ensure that ASP.NET is set up properly and otherwise manage the .NET installation.
Run the following command sequence to set up your Microsoft IIS web server properly.
//The "-u" flag uninstalls the current version of ASP.NET.
//The "-i" flag installs the current version of ASP.NET.
//The “-c” flag installs the client-side scripts for this version to the aspnet_client subdirectory of each IIS site directory.