i pressed the power button to turned it off, after i turned on again, it stopped at the picture of starting getting into system and full of green points, so i turned it off again.Eventually, i can even turn it on, it turns off in about 5 seconds: no display, no beep, no HDD light, only the power light, GPU light and fan turn on for 5 seconds then all of them was gone. i think there must be something wrong with graphics card.