When a Windows XP SP1 wireless Zero Configuration (WZC) client computer is in the proximity of two wireless access points, if the Preferred Networks access point is NOT broadcasting its SSID (Service Set Identifier) and the other access point is broadcasting its SSID, Windows XP SP1 will automatically connect to the access point that is broadcasting its SSID.

NOTE If your computer is connected to an access point that is NOT broadcasting its SSID and another access point in the proximity broadcasts its SSID, your Windows XP SP1 computer will connect the access point that is broadcasting its SSID.

NOTE: You should NOT disable SSID broadcasting. All access points must broadcast their SSID to identify themselves to potential clients.

NOTE: See The Windows XP Wireless Zero Configuration Service.