Can't load web pages

OK. This problem occured earlier tonight. I use firefox and connect to the net through a router. I rebooted the system just because it'd been on all day and I suddenly couldn't access google. On closer inspection it's the same for yahoo, hotmail, and any microsoft site.

The same thing happens in IE and Opera, I connect to game servers fine and I can send e-mail via outlook but I can't sign into MSN and sometimes I can get certain frames of the hotmail main page to load.

This has occured suddenly. I tried to use an independant ADSL modem and not the router but as windows blows it took ages so I lost the will to live.

Everything has access through the firewall before anyone says that. I can load this page and other by typing, but I can't search for anything as google, jeeves nothing will load.

Any help is greatly appreciated.