if your phone line is close to your computer consider testing it with the supplied modem (or any other adsl modem you have) to ensure that the connection is fully working.
Also is it possible the router is connected to the internet but your pc is not connecting to that router when trying to connect to the internet? If you have a good admin area in your router you should be able to look around and see if it has obtained an ip number and wether it is fully connected.