My old network was fine. Computer A is upstairs, Computer B is on the same level as the router, but about 50 feet away, and Computer C is in the basement. I upgraded to the WPN 824 to increase the connectivity for Computer A upstairs, and it worked. However, Computer B suddenly lost connectivity. It couldn't see the network. It had a Netgear MA301 card. So I switched it to a D-Link G 520 card. I have 100% singal strength but no connectivity. It isn't a firewall or AV problem. I'm set to Infastructure, channel 6. The setup software for the router can't seem to set to Ad Hoc. Help.