The tampered message usually means that the terminal is not in its original state, possibly disassembled during refurbishment. Although you'll probably not be able to clear the message permanently, you should still be able to use the terminal. Keep pressing the red cancel key until the soft pay menu appears. If that doesn't work, the terminal may need to be replaced. Also, try unplugging the terminal and then pressing the F2 and F4 keys together while reconnecting the power. This should bring you to the system mode menu. Password is 1 alpha alpha 66831. Once in the system mode menu, you should be given an option to restart the device. Not guaranteeing this will work, but it has for me in the past.