I've seen this! I was using Norton 360 and its firewall module was forcing my wireless network to always disconnect. It usually occurred 5 minutes after a reboot or wireless adapter reconnect (USB.) Turned out my Norton 360 must have been "told" which wireless network SSID to trust. I have since "abandoned" most Norton security products, due to an on-line support agent who "crashed" my XP set up. After that crashed, I was forced to re-install the XP.