Click on Properties once you select the wireless network that is having problems.
Click on the Authentication tab and now uncheck the Enable IEEE 802.1x authentication for this network box.
Automatic wireless Internet / Wi-Fi network configuration will be disabled if this checkbox is unchecked.You must be logged on with Windows XP administrative privileges to enable / disable this feature.By default, Windows XP enables its automatic wireless configuration support.Many people mistakenly assume this means your laptop will automatically to any wireless network it finds. By default, Windows XP only auto-connects to Preferred networks.First, click on the wireless icon in your taskbar and under Related Tasks, choose Change advanced settings.
Now click on the Wireless Networks tab and select the network in the list at the bottom.
This list represents a set of known Wi-Fi routers or access points you wish to automatically connect to in future.
You can "Add" new networks to this list by specifying the network name (SSID) and appropriate security settings of each.
The order Preferred networks are listed here determines the order that Windows XP will automatically attempt when seeking to make a wireless / Internet connection.
You can set this order to your preference, with the limitation that all infrastructure mode networks must appear ahead of all ad hoc mode networks in the Preferred list.
The Wireless Networks tab allows you to access the set of "Available" networks.