Try and see if you can get it to restart in "Safe Mode". If you can get the tablet to fully load in "Safe Mode", then you probably have an app (or few) on the device that is causing the issue. You would need to find and uninstall them.
To get into "Safe Mode" please do the following.
1. First turn off the tablet.
2. Next press and hold "Power" until you see the manufacturers logo on the screen, then release the power button.
3. "Quickly" press "Volume Down" and hold it for few seconds until you see the message "Safe mode: ON" or something similar.
4. If you wanted disable it, simply repeat the steps above, and you should see "Safe Mode: OFF" rather than on.