I know this is an older post, but recently came across this same issue, and wanted to post the fix in case someone else came across this. Just re-setup a Netgear wireless access point with 2 netgear repeaters. The configuration required me to use WEP. After setting it up, everyone else was able to get on except one laptop - a Lenovo running XP Pro. Was getting a wierd Certificate error. I knew it was bogus, so I went in and made sure the old SSID profile was gone (Control Panel - Networking - Wireless Properties - Wireless Networks Tab, then remove the SSID). Then I set it up MANUALLY. After that it worked. For some reason, trying to select it from the list of available wireless networks doesn't seem to work.