We just bought a new Dell Inspiron 660 -- and are trying to set-up WiFi.  The computer sees our neighbor's WiFi networks, but not ours, even though it is sitting only a few feet from the wireless router/gateway.  Not only that, but we have several devices and computers that are all working fine on our home WiFi network.  Our home router is 802.11 b/g -- and looking at the new computer it is 802.11 b/g/n.  Any ideas why the new computer won't "see" the closest/highest signal strength network in the house?