Running Visual Studio 2010 Asp.Net web code using the Local IIS Web server Version 7.5 (Windows 7 x64), I came across the error:-
Unable to start debugging on the web server. Unable to connect to the web server. Verify that the web server is running and that incoming HTTP requests are not blocked by a firewall.
Open IIS - Control Panel - System and Security - Administrative Tools - Internet Information Services (IIS) Manager
Expand PC/Server Name - Expand Sites - Select Default Web Site
Windows Authentication is enabled