Internet Browsers won’t connect (Windows 7)

I have 3 pc’s connected to the Internet via a Router. 1 pc has Windows Xp, the 2nd, Windows Vista. These work fine but the 3rd, with Windows 7 won’t connect to the Internet no matter which browser I use (IE7, or IE8, Firefox, or Google). I have re-installed IE twice. I can run Windows update and I am able to access it remotely. I can also ping and tracert to anywhere. Any ideas?