Wireless Modem

Hello,

A friend of mine from church had a laptop that kept freezing up on him. After installing Avast anti-virus and checking the computer I found it had a bunch of viruses, some that avast couldnt fix. I re-installed windows XP on his laptop (a Dell Vostro 1500) and now when I try to configure his wireless internet I don't even see a place to create a wireless connection. I checked hardware manager and his modems are listed with a yellow question mark beside them (I assume that means that the hardware isnt configured). I am a strict linux user just moved to windows Vista and know next to nothing about XP. Can someone help me please? If any more information is needed I will be happy to find out and tell you.