My dell studio

Hello,
my dell laptop will not connect to the wirless router in my house but it will connect to anyother router and it will connect to that router with a cord with no prob wut it will not let me connect to that router wirelessly why is that i realy want to use my laptop away from the desktop it used to work then my roomy used it and now it wont work there is no password on it or anything what happend help me when the laptop trys to connect it sez get closer or the configs arent right but i have tryed everything