Reinstall ASP.NET 2.0

When your IIS is installed after the .NET 2.0 SDK was installed, you have to prep the IIS server configuration manually or reinstall .NET SDK.

To manually configura IIS use ASP.NET IIS Registration Tool (Aspnet_regiis.exe) ,

Running: aspnet_regiis -i, does the trick when you get

[NullReferenceException: Object reference not set to an instance of an object.]
   System.Web.Hosting.ISAPIWorkerRequestInProc.GetServerVariable(String name) +1618
   System.Web.Security.WindowsAuthenticationModule.OnEnter(Object source, EventArgs eventArgs) +593
   System.Web.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +92
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +64