Hi your system is a TVT unit from china   And the password is 123456 ...... If this is not working then you might try the roomate option   Connect dvr to home network and from IE call it up with its local ip which is http://192.168.1.100   And use admin and admin as user and password .   Once in create another admin account under manage in menu ..... Once that is done then go back to dvr log in with your new account and delete all old ones.     If admin has been changed then only option in email to TVT with ser number but they do charge.