Reboot like this?
Reboot the iPad by holding down on the sleep and home buttons at the same time for about 10-15 seconds until the Apple Logo appears - ignore the red slider - let go of the buttons.
If that does not work, look here for help. Pay attention to the last part of the article that talks about restoring the device.
What to Do When Your iPad Won't Turn On
iOS: Not responding or does not turn on
iPad Frozen? How to Force Quit an App, Reset or Restart Your iPad
iPad: Basic troubleshooting