Compaq laptop internal wireless not working

I am trying to fix a Compaq laptop for a friend, that has an internal wireless card, with a button to press to turn on the wireless. She recently had to reinstall windows Xp and the blue wireless light does not come on when pressed, and you cannot connect to the internet, i checked for drivers and a couple are missing, including a modem one. is the problem that the driver is missing, or something else?