Application won't start in IIS

I have developed an ASP.net  Web Application with Visual Studio 2013.

1. In Visual Studio, when I start the application using IIS Express, everything runs fine.
2. In Visual Studio, when I start the application (F5) using Local IIS, I get the following error message "Unable to start debugging on the web server. Could not start ASP.NET debugging. More information may be available by starting the project without debugging."
3. In Visual Studio, when I start the application without debugging (Ctrl F5) usingLocal IIS , Internet Explorer shows an error page : "HTTP Error 404.3 - Not Found. The page you are requesting cannot be served because of the extension configuration. If the page is a script, add a handler. If the file should be downloaded, add a MIME map."

Can someone please explain the two error messages and please tell me how to set up my Local IIS ?

Thanks