Here's what to do:
First you will need to recover your iPad. Follow these instructions.
-> Turn off your iPad (press and hold the On/Off button)
-> Press and hold the Home button on the iPad
-> While holding the Home button, connect the iPad into a computer that has iTunes installed (use the USB cable to charge the iPad). If your device doesn't turn on automatically, turn it on. Don't release the Home button.
-> Continue holding the Home button until you see the Connect to iTunes screen.
-> If iTunes doesn't open automatically, open it. iTunes will alert you that it has detected a device in recovery mode.
-> Click OK, then restore the device.
If your device doesn't go into recovery mode, try steps 1–4 again.
In case you don't have a backup, you will need to reconfigure your iPad from scratch
For help doing this, see