I just kept resetting the router the router via the pencil method until it worked.My wireless network isn't currently encrypted/secured, if yours isn't either then someone might have pushed the "synchronize security" button, I think that's what happened to me.2) Reset the router by holding in the button for 15secs until the lights indicate that it has fully reset.
Windows xp validating wireless connection
(11) When you go to connect to FREDsecure now, you will be prompted for a Username and Password.
1) Click the Start button at the bottom, then select Control Panel, then Network Connections and right click on your wireless network card and select Properties. Uncheck and turn off Automatically use my Windows login name and password.
I've read through the other answers and comments and I can't see any indication that you've tried to delete your wireless device from Device Manager in Windows, nor that you've deleted all known wireless connections on the device and started over. This may be a Windows problem and not a router problem. I don't know why the protocols on the card would be a problem. So, have you tried to delete your Wireless Conection?
Right click wireless card, properties, wireless networks, in prefered networks, delete yours. I went into my router settings, disabled the wireless network security, and tried to connect to it from my desktop. I tried setting the security back to "WPA-PSK and WPA2-PSK" and tried to connect. I experimented a little and found that it works find if I set the security to "WEP" or "WPA-PSK" but not "WPA-PSK and WPA2-PSK" and not "WPA2-PSK". Is that a good choice or is there some sort of risk involved with it?
NOTE: On some Windows XP computers, it is necessary to disable "Validate Server certificate" in order to have your username and password verified and to obtain a connection.
5) Click OK buttons and close any Windows to exit the configuration. Also, uncheck Authenticate as computer when computer information is available.(6) Now click the properties button and check Validate server certificate and make sure that Global Sign is checked under Trusted Root Certification Authorities.Note that this should erase all settings and will return it to the out-of-box state.If you have tried all other venues, then I would then go for this option. What makes you think that one of my other computers is reconfiguring the router?Well, best of luck...sorry I can't be of any more help. I also tried restarting it from within the built-in utility (192.168.1.254). My wireless card is internal, so it would be a little cumbersome to take it out and put it back in.