hp acer laptop won't shut down or restart

I was trying to show a friend how to use email. I turned the computer off and told her to restart and see if she could go to the email program. But, when I turned around she was waiting for the screen to light up. The start button is lit up. I can get no response from anything I have tried. It won't turn off or come fully on. I tried unplugging it as I would my desktop, but of course the laptop had it's own battery supply so unplugging had no effect. Any suggestions?

Hold down the power button until the laptop shuts off. You can pop the battery out after that.

Thank you Midknyte. This shows my stupidity, I know, but your response helped me very much, and got me past this. I have never used a used a lap top. Thanks again!