How can run asp.net web application using IIS 7?

Question

Server Error in Application "DEFAULT WEB SITE"

Internet Information Services 7.5

Error Summary

HTTP Error 404.3 - Not Found

The page you are requesting cannot be served because of the extension configuration. If the page is a script, add a handler. If the file should be downloaded, add a MIME map.

 When a create a virtual directory and then run it show this error.

Thanx