I've just installed Visual Studio (Ultimate) on my development machine. The install seemed to go fine, but when I try to run a VS2012 ASP.NET Web Application project, IE launches and gives me:

IIS Express is installed, and the project is set to use IIS Express:

IIS Express is running, the port is open etc, but it doesn't appear to be serving any webpages. If I look in the IIS Express logs, I can see the requests being returned with what looks like a 303 error:
2013-12-23 14:22:49 ::1 GET /login.aspx - 25869 - ::1 Mozilla/5.0+(compatible;+MSIE+9.0;+Windows+NT+6.1;+WOW64;+Trident/5.0) - 303 0 0 0
2013-12-23 14:22:53 ::1 GET /login.aspx - 25869 - ::1 Mozilla/5.0+(compatible;+MSIE+9.0;+Windows+NT+6.1;+WOW64;+Trident/5.0) - 303 0 0 0
Any ideas what I need to do/undo to get VS2013 running my project?