Maybe try updating the drivers. I doubt that would be it but since everything else has been tried. If not reformat like celegorm said. i know that has helped me a couple times when i tried everything i could think of. Pain in the ass i know.
do u have a firewall set up because it only takes seconds to get a virus and reboot it up dont have the card in there, set up a firewall and all of that jazz and then insert the card