XP home Dell laptop, working normally for over a year using WiFi to connect to the Vodafone home fixed line broadband connection, no other PC,s on the network. Stops working for no apparent reason, the laptop connects to the router and recieves an IP address but cannot connect to the internet or ping the router. Tried two other routers both the same. Network Cable connection works on all routers. I then tried a new router with no encryption and it connects no problem, dissable encryption on the other routers and they connect ok. So with encryption I cannot connect using WiFi to any router and without all is ok, whats going on