I can connect my laptop to the router but it won't connect to the net. In the sharing centre I have the 3 icons showing the laptop connecting to the "unidentified network" and then a red cross on the connection to the internet. It connects when plugged directly into the router, and my apple mac's connect no problem, as do all iPhones. I'm not really a PC/Windows person so am at a loss, any help is gratefully received, my kids are moaning like hell.
Have you recently updated your firewall? I had the same issue and it turned out that when I upgraded from AVG Internet Security 9 to 2011 that the Firewall settings had changed and it was blocking my access to the internet.