Linksys needs certificate?

Okay so recently, i got a Linksys Router (WRT54G) %26amp; i connected it to the computer downstairs that is running through the cable modem. Everything works fine on that computer. However, when i try to connect on my other computers it tells me that it needs a certificate. I've entered the Encyrption key in order to get onto it, but then it pops up at my little computer and tells me "windows cannot connect because it needs a certificate",





Any help would be greatly appreciated.





However, i've already tried linksys support site and that did not help. So. =\
Linksys needs certificate?
downgrade your encryption to WEP from WPA, that would be the first place to start, especially if the computer that is having trouble is a little older than the others