Is there a way to test ti on another computer to make sure it's dead? If indeed it is dead and it's not the port, or just the system not registering the connection, there is no way to fix them. If you can't see it, you can't try putting a file in it. Therefore, the only way to test it would be on another computer. Don't throw it away, I have never seen one die, they have no moving parts. Have you changed the settings or upgraded your computer lately? iTunes is a good place to test it if it will show up, if not, it's really difficult to say?
Ray