Where do I find IIS? In which folder?

Version 1.1 Virtual directory?what is it? never heard of it. don't know what it is .

This is the error message received when tried to open ASP.Net "The Web server reported the following error when attempting to create or open the Web project located at the following URL:'http://localhost/WebApplication1'. 'HTTP/1.0 503 Service Unvailable'" Anyway I have IIS installed What should I do to run my first ever ASP.NET application