Remove the AC, the battery and hold the power button for over 10 seconds. Now put the battery in, the AC and try again.
Sorry, I can't guess what happened. But I will share a common reset.
Ok I have an Acer laptop. It's an older model but it still works fine. I've been using it for about 2.5 years. Today I was watching a video and suddenly my computer goes into hibernation. I'm almost positive I didn't hit the hibernation button or anything. And now it will not turn back on no matter what I do. I've tried removing the battery, unplugging it, all of that and still nothing. The weird part is, when I hold down the power button for about 2 seconds, the battery indicator LED flashes repeatedly for a short time. What could have happened?? I'm sure it wasn't a virus because I keep my computer clean.