as lame as this sounds, make sure the switch for the onboard card is on if there is one. (I cant count the number of people I had to help becasue they over looked a power switch for the card) also try an external card. make sure you dont have both windows and a 3rd party program trying to manage wireless, that is bad. and make sure you have the correct setting in the correct managing tool. most laptops come with their own tool to manage the wireless so it fights with windows to chose the connection and causes problems. try reinstalling the drivers for the card also.