wireless is connected but cant connect with any browsers

I have 2 identical laptops HP pavillion dv8000, they both connect to my wireless router with no problem and 1 is fully functional online , the other will not connect with firefox ,aol or internet explorer and all programs will not connect either . yet the toolbar icon for wireless connection says it is connected I have tried several diffent remedys including installing a cellular wireless modem to no avail.both systems are running windows xp media center.
any suggestions would be appreciated.