online login

Very unusual problem. After a power outage internet via broadband is working but unable to login to programs online. MSN won?t login and 2 online games won?t login. They time out just as if there is little or no connection. Surfing and downloading is normal @ normal speeds. 3 PC’s connected to the router have all experienced the same problems. They can?t connect using there own accounts. Id say something with the 4 port router but what? Done so far: powered down 4/router 10min, run up to date anti-virus and spyware.