Getting a 404 error on your newly configured ASP.NET website? When I went to /localhost/mywebsite/ I didn’t get anything, all I got was a 404 error.
If this is happening to you, make sure to go to:
Control Panel > Programs and Features > Turn Windows features on or off Internet Information Services > World Wide Web Services > Application Development Features
Make sure your version of ASP.NET is checked (mine was ASP.NET 4.5). This will check a bunch of other things in the dropdown like ISAPI Filters and .NET Extensibility, that is fine.
Click ok and run iisreset. This should make the problem go away!