There are two desktops and two laptops in my house, so naturally, I have a wireless network. The computer that is connected to the modem and router somehow can't use the Internet. All the other computers' connections are fine. The defective one says it's connected and says the signal's strong, yet when I connect to the Internet, there is a message that says either "Server not found" or "Connection timed out." Any help would be greatly appreciated.