Wireless connection.

My wireless was working just fine a week ago. I usually use my college wireless by providing my username and password. about three days ago I was unable to connect to the internet. I receive reception bars and it seems as if i am online but however i cant access any web pages. I tried going to a nearby coffee shop that offers free wireless and the same thing happened I joined the coffee shop's network by inserting their password and it accepted the password and the wireless icon showed as if i was connected but i cant access any pages.
Any suggestions?
Thanks

sorry it is a 2.26GHz Intel Core 2 Duo processor, MacBook
built-in AirPort Extreme 802.11n Wi-Fi.

not sure if I can help, but someone else might be able to solve your problem if you post more info about your computer. Specs, OS, wireless router etc

2.26GHz Intel Core 2 Duo processor, MacBook

built-in AirPort Extreme 802.11n Wi-Fi.

Take a look at the Wireless Connections FAQ sticky to see if it can help you track down the problem.

And here's another good wireless connections fixit LINK that may help.

Let us know if you need more help.

Regards.

My macbook was doing this. Turns out I was typing the password in wrong(wasn't capitalizing the letters that needed to me) Maybe this isn't the issue with yours, but double check to make sure you're capitalizing every letter that needs to be.

Jos - Have you tried shutting down the MBP and restarting - and i guess you are on 10.6?