Windows was unable to find a certificate to log you on to the network

Can someone help figure out this problem with one of the laptops in my network please. I have a D-Link DIR-655 router, current on the firmware. Using WPA/WPA2 - Personal , AES encryption.We have several computers, 2 of them using wireless n, an ancient desktop using a Linksys wireless G USB adapter and an old Sony laptop with no built in wireless.
The old Sony can no longer connect to the wireless network unless it is plugged in on the Ethernet connection, using the same Linksys USB connection( a WUSB54GC) that connects the old desktop without any problems gives me a connection to my router but no IP address, and a constant pop up from windows saying Windows was unable to find a certificate to log you on to the network. I've tried setting a static IP, repairing the connection, checked the network properties to make sure IEEE 802.1x authentication for this networkis unchecked(it's totally grayed out) What settings am I missing?:confused

 

For anyone else looking for an answer I may have found the fix, here
http://support.microsoft.com/kb/893357 and the download here
http://support.microsoft.com/kb/917021/
First I will try Service pack3, if that fails (the computer is really old) then I'll try the patch update. I'll post the results.

 

Got it!, service pack3 installed and the problem is fixed. Thanks to anyone who tried to puzzle it out for me.

 

Appreciate the troubleshooting and feedback.
This will help other users in the future.:major