After many years of use without any problem, I did a system shutdown in a electrical stormy night and unplug the power cord. At the next day when the power cord was plugged, the power supply made the "click" sound from the relay and that is all, no chime, no fans, nothing. I remove the power supply and have it checked, the technician said that is not good. The power supply was replaced with a good one with the same part number, again nothing. Then the battery was replaced (the old battery is dead) and reset the PMU, this time the fans start, the DVD unit makes a sound like as it want to activate the tray, but no chime, no video, no disc spin, no error code in leds. Could somebody tell me how to do? Thanks in advance.