How to get dynamic web page content in C#?

I'm programming a Windows Forms based web crawler which should do the following:

1) Start from a URL defined by user (for example www.microsoft.com)
2) Download the content of that page and scrape specific data (strings)
3) After going through page content, add all the data found into an existing database
4) Find all the links on the page, select 5 of them and create new crawlers to crawl each of them.
5) Each crawler starts again from stage 1 with their unique URLs.

Now the problem is that when I download a webpage using WebClient-, HttpWebRequest-, or WebResponse class (all in System.Net) I only get the static content of the web page. Most websites contain scripts, php code and other dynamic content and I can't see them with these classes.

Simply:
Let's say I have a php page www.example.com/page.php and when shown in web browser it gets 100 names from a database and prints them on the page. I want to be able to read that dynamic content in my Windows Forms application using C#.

This is just an example, the page could be for example ASP.NET and contain news headlines or something like that. I can't define what URL's the users will scrape so I really have to be able to read static and dynamic content from any URL.

NOTICE! The problem is clearly stated above, I don't need help in implementing any other features listed on top of this question :)

Thanks!