No wireless credential pop-up.

configure wireless access via AP (throught RADIUS server) using windows
wireless network setting. it prompts for credential page for the first time.
after enter the user account, it connected to the wireless network. But the
credential was "remember" by the laptop. I reboot the laptop, it
automatically connected to the wireless network without prompting the logon
page. it happens on various brand of laptops and various type of wireless
adapters. how to configure such that it will always prompt for credential
pop-up everytime the laptop boot-up?

2Tian