Not every device is perfect, even your trusty iPhone or iPad. On rare occasions, an app might crash or the screen may stop responding to touch. Even worse, a OS upgrade might go wrong part-way through the update. In these rare occasions there are three solutions:
1. Perform a hard-reset
This forces the iPad to restart and cleans its cache of memory. To do this, hold down both the power button and Home button until the screen turns off. This might take anywhere from 5-10 seconds.
2. Let the battery run dry
If the hardware buttons are stuck or broken, then simply let the battery run dry. Note that this might take up to 10 hours.
3. Erase and restore the iPad via recovery mode
This is a bit drastic, so only perform a wipe and restore if the Apple logo has been stuck on-screen for more than 10 minutes. This might happen during a software update, for example, while upgrading from iOS 6 to iOS 7.
First, perform a hard-reset (see above). Next, plug your iPads USB cable into your computer, then hold down the Home button as you plug the cable into your iPad. When you see the Connect to iTunes screen appear on the iPad, release the Home button. iTunes should then display a message such as: “iTunes has detected an iPad in recovery mode. You must restore this iPad before it can be used with iTunes.” Next, use iTunes to restore your iPad using a recent local or iCloud backup.