If you have a 3rd-party connection manager like the Intel PRO/set or Atheros ACU et al (Broadcom makes one too), it's trying to control the wireless. Find it, and in its options/preferences, tell it to let windows control the wireless card. If you can't find any way to change that setting, then you'll have to uninstall it from Control Panel, Add/Remove Programs. But most of them I've seen would co-exist with WZC if you tell them to let windows have control.