Reading particular contents of a web page

Question

I have an windows application which accesses a website.
I used webrequest and webresponse classes to read the webpage.
But this gives the entire html of the webpage.
HOw do i access any particular part of the webpage.???
For example - if i read the google news page then i get the whole html of the google news page.
how do i read only the news content of the page???

TIA