While doing some refactoring with the project, I suddenly start getting HTTP 404, and that to for all pages that exists and was working few minutes back. I was amused to get the error, with the fact that pages existed, I could see them and feel them! After a while, I noticed that I have deleted a existing .aspx file from project which I forgot to remove from spring.net configuration file.

If you add any .aspx in Spring.Net config that do not exists, Spring.NET brings you to yellow screen with appropriate message. But not when you delete one from project and forget to remove from config file! At least not all the time.