Introduction
A common error when we developed web sites is that we forget to manage the error 404 (resource not found), so I will show how to manage this problem easily in ASP.NET MVC.
Using the code
First, create a new ASP.NET MVC 4 Project using the basic template, this template looks like:

Next, add the package NotFound MVC using Nuget:

When the package is installed, you can see that a new view was create at the folder Views/Shared:

Now, if you run the application, automatically you are sent to the NotFound view:

The next step, is that you personalize the view.