My ipad suddenly has a grey screen and is unresponsive.

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

Home button not working or unresponsive, fix

http://appletoolbox.com/2013/04/home-button-not-working-or-unresponsive-fix/

iPad: Basic troubleshooting

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

 Cheers, Tom 😉

You can read the troubleshooting steps in this support article, but pay attention to the parts about resetting the iPad and restoring the device. Try the reset first. Your issues probably has nothing to do with an app.

iPhone, iPad or iPod touch: Not responding or does not turn on