I've just deployed a previously (on my local IIS) working MVC4 app to IIS 7.5 on the dev server. After tweaking this and that - one knows how these things get forgotten - the app finally launches, but shows a directory listing of the app root. Clicking on most links there works, opening the directory listing of the subdirectory.
Elmah logs no errors and /elmah.asd also gives a 404. The site has an appropriate localhost binding in the hosts file. I can find nothing wrong. MVC is installed on the server, as another MCV app works fine