It could be the router. I had the same problem with my iPad, which suddenly would not connect and said the password was incorrect when it wasn't. I logged into my router control panel, and the Wireless control setup. Then changed the setting of the WiFi network to None on the security options. Then logged back in with the iPad without the need for any password. That worked. Then I went back in to the Router Wireless Control and changed the Security option back to WPA2. Then logged back in to WiFi on the iPad, this time putting the password back in when prompted for it. This time it accepted the password. Bingo!