I'll go with
hrdwareguy here -- my best guess is that DNS is failing for some reason. Try going to the following URL:
http://216.239.33.99/
That's Google's IP address. If that works, then you need to contact your ISP and enter the correct DNS information, they can tell you how to do that.
If that *doesn't* work, then perhaps it thinks you're connected, but you really aren't.
That's my best guess based on the information here....good luck!