Asus eeebook will not turn on

Hello, my asus eeebook won't turn on. I have had similar problems before and fixed them by manually restarting, but this time is different. I press the power button, and the green and orange lights flicker on for a second. I hold it down for about 20 seconds, and it starts to power up, but if I let go of the power button it blacks out again. It had half battery before I plugged it in, so I know it's not a faulty charging cord. Please help as soon as possible, thank you!