3 things I can suggest
1) See if there is a firmware update for the router and install.
2) Visit your motherboard manufacturer's website for the latest NVIDIA lan driver to install. It may be part of the chipset package, or stand alone.
3) From one of the wireless pcs, go to the router's configuration page and make sure that there isn't any mac address filters set against it. Or alternatively, check that it is specifically allowed if that's how the router is configured to operate.
If all else fails, setup a static ip address in Windows for the network. You'll get access this way for sure.