It's hard to see where did you screw up this without seeing all your steps. Usually, running a valid ASP.NET application presents no problems.
I would advise the following: create a simple Web site from scratch. The URI http://localhost is used for testing/debugging on an development computer under the HTTP server bundled with Visual Studio. When you do everything from scratch and hit "Run" for the very first time, this "development HTTP server" is started. You will get a window where you can choose a URI to load first, one of those available in your project. When you do the basic exercises, you might be able to see how to revive your legacy project. If you wish, you can run any other HTTP server, but it won't let you debug your server-side code and it has to support ASP.NET.
My other advice: from your legacy project, remove everything which is not a pure source code. Build and start it from scratch. Naturally, you should clear understand what is source code and what's not, no matter what work do you do. Remove all "obj", "bin", "*.user", "*.ncb"… Sometimes, project clear operations (from project menu or Solution Explorer) helps, but cleaning it manually before even starting Visual Studio is the most sure method.
Learning ASP.NET? I think there is nothing better than starting from http://www.asp.net/get-started