Open command prompt and do an ipconfig /all
(You could post thisinfo and it may help others to diagnose your problem.)
This will tell you if you have an IP, and dns. This may tell you if your connected really. Also try pinging an ip address NOT and web address like
this is yahoo. If you get a response from this but get no response to
Then it means its a dns issue.
Check network settings that the network settings are configured to automatically pick up dns and ip and all other settings.