Shows connected but really not please help!!!?

i have a laptop upstairs and it has a wireless card. Yes i have wireless internet downstairs. when i connect it shows "connected' on the bottom right. though when i click on internet it shows "cannot display webpage" for any website i try. The signal strength is excellent and everything. i already tryed to reset my IP and that didnt solve the problem. please please pleeeeeease help i really need your advice. THANK YOU!!! (Windows Xp) its a lenovo thinkpad. and i connect to a unsecured network so i dont need a pword. please help