I have an optiplex model name:dcne serial number: . It was working ok but today when I tried to enter windows from hibernation it started turning on and off endlessly with no signal on the monitor. I unplugged it from the power, plugged it again and the same thing happened. From the moment I put DC power cable on it continuously turns on for 5 seconds and turns off, it stays like that for 3 to 5 seconds and then turns on again, not showing anything on screen.