The Internet Company just had a repair job for a laptop, which when the user tried to log in using Windows XP Professional, would display a box for nearly a minute saying "802.1x Authentication Status" and a message "Windows is waiting for the wireless network and DHCP — Google didn't help much, so we had to guess a lot. She wasn't using 802.1x at all, she'd only used public networks. There was nothing indicating that it should use 802.1x at login time, no group policy setting to force it, nothing. engnyath found several good-looking but ultimately fruitless Microsoft KB articles.
The fix? Uninstall the driver for the wireless card and reinstall. I suspect that there was a registry setting that was reset by doing that. If I could reproduce the problem, I'd figure out which, but we're in good shape now and going to call it done.