Sometimes I have encountered problems with SharePoint sites so that they do not work. One of the quick solutions I have found is to simply create a new web application. Remove the content database from you actual application and connect it to your new application.
This is not something you want to do in a production or test environment BUT if you are in a hurry and you are wondering why your web application is not working and after all check everything seems OK(also check your DNS settings). Then you could consider this option in your development environments.