1. Try doing a hard reset:
Press and hold both the Home button and the Sleep/wake button simultaneously for about 15 seconds and release when the Apple logo appears. <=== is this what you've tried??
2. If that doesn't solve the issue, backup the device and restore it as new.
In that case, use: http://support.apple.com/kb/HT4137
NB: set up as a NEW device because a software issue will be in the backup. If the issue persists after restoring as new, you should offer the device for service.
If you get specific error messages/codes in iTunes when updating/restoring, check this: http://support.apple.com/kb/ts3694 for causes and solutions
If you're not able to restore the device, you should use: http://support.apple.com/kb/HT1808
Using that last article will erase everything on the device, so make sure you have a backup!
Frozen or unresponsive iPad
Resolve these most common issues:
• Display remains black or blank
• Touch screen not responding
• Application unexpectedly closes or freezes
iPad Frozen? How to Force Quit an App, Reset or Restart Your iPad
What to Do When Your iPad Won't Turn On
iOS: Not responding or does not turn on
iPad: Basic troubleshooting