I have some troubleshooting tips for you to attempt for resolving this issue. The article I'm linking to you is written for the iPhone, but the same troubleshooting steps for this issue will still apply for your iPad:
- 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.
- Check if a Liquid Contact Indicator (LCI) is activated or there are signs of corrosion. Learn about LCIsand corrosion.
- Connect the iPhone to the iPhone's USB power adapter and let it charge for at least ten minutes.
- 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.
- 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.
- 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.
- If restoring the iPhone resolved the issue, go to step 4. If restoring the iPhone did not solve the issue, seek service.
If you are still experiencing issues after attempting those troubleshooting steps, then you may need to see these additional steps at the end of the article:
Issue not resolved
My issue is still not resolved. What do I do next?
Thanks for using the Apple Support Communities!
You didn't give us much Togo on but the first thing ID suspect is a drained battery. Plug the iPad into the charger that came with it and plug that into a known good wall outlet. Leave it plugged in for at least an hour. It may take that long for the iPad to respond. After an hour, and while still plugged in, reset your device. Press and hold the Home and Sleep buttons simultaneously until the Apple logo appears. Let go of the buttons and let the device restart. If the iPad restarts leave it plugged in until the battery reaches full charge.
You might have accidentally rebooted it.
It sometimes happens even if you didn't hold down the home and power button altogether, its happened to me once.
My ipad froze and I tapped the home button and the power button several times (home button first and then afterwards I started pressing the sleep button) and it caused it to reboot.
Try holding the power and the home button at the same time.
I agree with Ralph9430...this is usually the symptom of a dead battery. Connect it to the external charger (using a PC's USB port may not supply enough current to charge the battery correctly) and see if it starts up or gives some kind of visual indication that the battery is being charged. If so, leave it on the charger for a few hours.