I am trying to write my first ASP.NET website and I really want to use the Twitter Bootstrap but I\'m failing at the first hurdle.
I downloaded the Zip file from her
You're using Twitter Bootstrap 2.0, but the tutorial was written for Twitter Bootstrap 1.0, there has been quite a few changes to the markup you need to use to get the desired look.
It explains some of the changes to the navbar component in the changelog, there are also some basic examples of how it is done now:
http://getbootstrap.com/2.3.2/getting-started.html#examples
http://getbootstrap.com/2.3.2/components.html#navbar
Also (unrelated to the question), you're including both the minified version and the standard version of the css/js, you only need to include one of each.