my ipad screen is black and it wound come back to nomal even if i try to reboot it,and if am offing it,i see blue screen and suddle it goes back to blank.pls help me

It sounds like you have the 'screen curtain' feature of VoiceOver enabled. You can disable it by doing a 3-finger triple-tap gesture.

You can also use iTunes to disable VoiceOver: press "Configure Universal Access" from the device sync screen.

Try this - Reset 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. (This is equivalent to rebooting your computer.) No data/files will be erased. http://support.apple.com/kb/ht1430

Frozen or unresponsive iPad

Resolve these most common issues:

• Display remains black or blank

• Touch screen not responding

• Application unexpectedly closes or freezes

http://www.apple.com/support/ipad/assistant/ipad/

iPad Frozen, not responding, how to fix

http://appletoolbox.com/2012/07/ipad-frozen-not-responding-how-to-fix/

iPad Frozen? How to Force Quit an App, Reset or Restart Your iPad

http://ipadacademy.com/2010/11/ipad-frozen-how-to-force-quit-an-app-reset-or-res tart-your-ipad

Black or Blank Screen on iPad or iPhone

http://appletoolbox.com/2012/10/black-or-blank-screen-on-ipad-or-iphone/

What to Do When Your iPad Won't Turn On

http://ipad.about.com/od/iPad_Troubleshooting/ss/What-To-Do-When-Your-Ipad-Wo-No t-Turn-On.htm

iOS: Not responding or does not turn on

http://support.apple.com/kb/TS3281

iPad: Basic troubleshooting

http://support.apple.com/kb/TS3274

 Cheers, Tom 😉