Dude, here's the thing, first of all, install Microsoft's Web Platform. There are all the applications needed to deploy your application in IIS.
Ok, downloading and running Web Plataform, first of all, install IIS Express, which is the free one that is available for download. It's simple, and you've already done it.
Downloaded IIS and configure the application pools for the version of Asp.Net installed (v4.0).
- Here's a tip, to access IIS go to the start menu > run > type inetmgr, done this will open up IIS, and make sure your application is in it, it is probably returning 404 because your application is not in IIS.
After installing IIS, install Web Deploy as well
What I do for my application to work in IIS and run my application: I deploy VS (and for that you should be running it in Administrator mode.) Right click on the VS shortcut and
Okay, you ran the VS, open your project and right click and go to the "Publish" option. When clicking you should create a profile and choose one of the options available to deploy in IIS and then, VS does everything for you.
You gave the deploy right, go in the browser and type in the address bar "localhost". If IIS is running without problems will appear an image that is an official pro website link from IIS from Microsoft. Ok, the image and such appeared, then type in the address bar "localhost / project_name" and hit enter. Ready your project will run smoothly.
Here I am not passing database server installation steps, because this is not the question ok?