The ! symbol usually appears when the device has too little battery power to run. Try connecting the device to a different USB port on your computer. If this does not work, then disconnect from any power source and press the play/pause button until the "!" symbol stops showing up. This is going to drain your battery completely. Then, when the "!" icon no longer shows up, connect to a power source. It may take several minutes for the device to show the home screen. Check the lower right side of the home screen to make sure the battery is charging.