Ok, a few days back, my mom was on the pc playing a game. All of a sudden, the pc powered down for itself. After pressing the power button a few times, it still was not coming on. I thought it was teh power supply,i got a new psu, but after installing it, the pc still would not come on. Also, when pressing the power button, no lights are seen and no sounds are heard. I changed three RAM sticks and it still has had no effect. Is my mobo dead? Any help will be appreciated.