Make sure the system is plugged in. If it is plugged into an outlet controlled by a switch, or is plugged into a surge protector, make sure those devices are powered on.
When you are sure that the system has power, unplug the power cord and plug it in again.
Press any button on the remote control. This should power it on and it should work properly again.
If the problem is not fixed, unplug it then plug it back in again.
Press any button to power the remote control on.
Press the up and down buttons at the same time. This will start a timer, it will count backwards from "10" to "1." Two dashed lines will then appear followed by the code "C1." After you see "C1" let go of both buttons.
Press both buttons at the same time again and you will see code "1C." Let go of the buttons one last time and your settings should be back to normal and the controller should work properly.