No Wireless on bootup (XP Pro)

I am having a problem with an Acer TravelMate 6413 wireless connection. I am connecting to a Domain, but the wireless connection hasn't picked up any AP's, thus not being able to recieve an ip address from the DHCP, and not being able to logon to the domain. The internal wireless on the acer's are the Intel(R) Pro/Wireless 3945ABG Tri-Band. and i this is happening on several models of AP's. Any help into fixing this problem will be greatly appreciated.