Q: My iPad keeps freezing and shutting down just after I purchased an itunes movie.

Hello, BRIABUNNI. 

Thank you for visiting Apple Support Communities.

Here are a couple resources that have some helpful troubleshooting steps for this issue.  These are labeled for the iPhone, but the steps will also apply for the iPad. 

Resolution

1. If a single application is not responding or stops responding when it opens, you can force it to close.
2. If the device is unresponsive or if certain controls aren't working as expected, restart your device.
3. If the device remains unresponsive or does not turn on (or power on), reset your device.
4. If there is no video or if the screen remains black, verify that the device has enough charge to turn on:
   1. If you are using an iPad, ensure that it's connected to the USB Power Adapter supplied with the device.
   2. Let it charge for at least twenty minutes, then see if it starts normally.
   3. If there is no image on the screen, press the Sleep/Wake button to attempt to wake the device.
   4. If the screen displays a red battery icon, continue charging the device until the battery is fully charged. Learn more about charging iPhone and iPod touch, or iPad.
5. If the above steps do not resolve the issue, or the if the screen remains black or shows a persistent Apple logo, try restoring with iTunes:
   1. Connect the device to your computer and open iTunes.
   2. If the device appears in iTunes, select and click Restore on the Summary pane. Learn more aboutrestoring iOS software.
   3. If the device doesn't appear in iTunes, try to force the device into recovery mode, and then restore it.
6. If the above steps do not resolve the issue, contact Apple.

iOS: Not responding or does not turn on

http://support.apple.com/kb/ts3281

Will not turn on, will not turn on unless connected to power, or unexpected power off

1. Verify that the Sleep/Wake button functions. If it does not function, inspect it for signs of damage. If the button is damaged or is not functioning when pressed, seek service.
2. Check if a Liquid Contact Indicator (LCI) is activated or there are signs of corrosion. Learn about LCIsand corrosion.
3. Connect the iPhone to the iPhone's USB power adapter and let it charge for at least ten minutes.
4. After at least 30 minutes, if:
   • The home screen appears: The iPhone should be working. Update to the latest version of iOS if necessary. Continue charging it until it is completely charged and you see this battery icon in the upper-right corner of the screen . Then unplug the phone from power. If it immediately turns off, seek service.
   • The low-battery image appears, even after the phone has charged for at least 20 minutes: See "iPhone displays the low-battery image and is unresponsive" symptom in this article.
   • Something other than the Home screen or Low Battery image appears, continue with this article for further troubleshooting steps.
5. If the iPhone did not turn on, reset it while connected to the iPhone USB power adapter.
   • If the display turns on, go to step 4.
   • If the display remains black, go to next step.
6. Connect the iPhone to a computer and open iTunes. If iTunes recognizes the iPhone and indicates that it is in recovery mode, attempt to restore the iPhone. If the iPhone doesn't appear in iTunes or if you have difficulties in restoring the iPhone, see this article for further assistance.
7. If restoring the iPhone resolved the issue, go to step 4. If restoring the iPhone did not solve the issue, seek service.

iPhone: Hardware troubleshooting

http://support.apple.com/kb/ts2802

Cheers,

Jason H.