So, i was installing a graphics card today, and i didn't unplug the computer for some reason, the computer flashed on for a few seconds and the on and off again a few times. i unplugged the computer after that. once finished installing the card i attempt to turn the computer on, nothing. the green light on the motherboard is still on. and i also tried shorting out the power supply while it still hooked up to the computer and to my surprise everything booted up except the computer never booted does that mean my motherboard is toast?