In Windows XP While trying to connect to a wireless network, an error comes up saying that “Windows was unable to find a certificate to log you onto the network (Network name). Here’s how to fix Windows was unable to find a certificate to log you on to the network
1. Click on the wireless icon in your taskbar and under Related Tasks, choose Change advanced settings.
2. Click on the Wireless Networks tab and select the network in the list at the bottom.
3. Click on Properties once you select the wireless networkthat is having problems.
4. Click on the Authentication tab and now uncheck the Enable IEEE 802.1x authentication for this network box.
5. That’s it! Once you’ve unchecked that box, try to reconnect to the wireless network, everything should work fine.