Why can http://localhost not be found?

     
There can be different reasons for this behavior. You should check the following things:

Open "Services" from the administrative menu, and verify if the IIS Admin Service and the WWW Publishing Service are started.
Be sure, that you have created a defaultdocument. If not, simply create a file named default.htm and copy this into the root of your webserver.
Try to open http://127.0.0.1 in your browser. If this succeeds, you may have problems with the name resolution.