While it could be a hardware problem, I want to say that you simply have too many wireless signals going around the house. What bandwidth is your router? 2.4GH? More than likely that's what it is. Besides all those computers, do you own a gaming console and/or cordless phones (not to be mistaken for cellphones)? These could all be causing interference. Take a cat5 (ethernet) cable and connect your laptop directly to the router. Does it connect to the internet now? Since other computers can connect fine, this is not a router issue. So it has to be either too much wireless signals around the house, or a problem with the software/hardware of the network adapter. A third, yet not likely, scenario is that 2 of your computers are sharing the same IP address. Do you have any static IP addresses set up? Can you log in to your router and confirm that all devices connected to it have different IP addresses?