How to fix "An unhandled Microsoft.NET Framework exception occured in w3wp.exe"

Change the ApplicationPoolIdentity of the application pool for your project to an account such as Local System.

How to install ASP.NET MVC4 into Visual Studio 2010?

http://www.microsoft.com/en-us/download/details.aspx?id=30683

How to disable session in ASP.NET MVC?

Two levels:
Application level is in web.config
<sessionState mode="Off" />

Controller level
[SessionState(SessionStateBehaviour.Disabled)]
public class MyController : Controller
{}