There *has* to be a Chuck Norris joke here somewhere, but I'm too tired.
We need a lot more information, I'm afraid.
I'm assuming this is wireless? If so, what kind of card. (you can run the command /sbin/lspci and it should show up in the last three or four lines).
Do you know the gateway? (Possibly some of the info that you had to enter). If so, can you ping it?
ping -c4 <gateway_address>
If that works, that is if you get a response, then you can try
ping -c4 188.8.131.52
If *that* gets a response too, then you can try
ping -c4 www.google.com
Let us know the answers here, and that will help. (If it's not wireless, then the ping testing results will still be useful.)
Brief explanation--the -c4 limits it to 4 pings.
First, the pinging of the gateway tests if you can reach outside of your machine. If that works, then we ping an outside address, to make sure that you can get past the gateway. If that works, and the pinging of google fails, it means that connectivity is good, routing is good, but it's a DNS problem.