Internet Problem

Hi all,
I dont really post much messages to this group but now-a-days i am 
facing a problem in the internet connection at my place. Initially
may 
be a month back it was working fine until now when i log on the user 
name and password is authenticated and i am connected to the internet 
but i cant view the web pages as it says "the page cannot be
displayed"
I tried to change the lan settings(Tools-Internet Options- ) by 
automatically detecting them but doesnt work out. Can there be some 
sort of DNS error or something. The page doesnt get refreshed too.
The 
modem and the internet line seems to work fine. I also tried making a 
new connection by Dial-Up-Networking but the same problem persists in 
the new connection too.
The biggest wonder is that the same connection used to work a month 
back???

I would be glad if someone comes up with the solution.