I have spent days reading different threads and trying lots of stuff, but nothing has helped my problem. My setup is a home network with one desktop PC wired to an ActionTec router-modem on ATT DSL and 2 PC laptops on wireless. Everything works on the two laptops, but I cannot get internet on the desktop. However, I can successfully ping everything from the desktop including the router/gateway, the other computers, other IP addresses and web addresses.
I thought it might be the desktop-to-router cable or the wired side of the router, but I connected a laptop to the router with the same cable and turned off the wireless and used the LAN Connection and the internet worked fine.
The desktop even does automatic updates for BitDefender in the background, but the browser (IE8) won't open anything. When I click on Diagnose Connection Problems, it says I may have a Firewall problem. But I have the same problem with both the Windows firewall and the Router firewall OFF.