IIS 7 does not allow ports on Windows Vista
After reinstalling Windows Vista, Visual Studio 2005 & Visual Studio 2008 on my computer, I started having problems with using dynamic ports with ASP.NET.
When ASP.NET web applications are executed in VS 2005/2008, they may run on dynamic ports on the local server, e.g. localhost:12345.
This worked before the clean install, but now I found myself being incorrectly redirected to www.localhost.com:12345.
After struggling with this, I eventually found a solution here. If you face the same problems as I did, I hope that it helps you out.