It's mentioned on p.70 of the user manual.
"Turn off the power and hold the STOP (T) button on the
main unit for longer than 5 seconds (reset function)"
Keep in mind this erases all stored settings.
My system has been working great until last night. When I turn the system on, I get the "welcome to Samsung Digital" message, blue light comes on but immediately it powers off and as it is I get a message saying "protect". Any button I hit then goes through the same sequence as I just mentioned above. I can't get the system to stay on. My Samsung tv works fine and my tv speaker works but I can't use my sound system. Any ideas or advice? I find no mention of this problem in my manual unless I am overlooking it. "PROTECT"--what does this mean? Please help if anyone can.....thanx in advance!!