Try starting it up in "Safe Mode" and see if it will load in there. If it will, then you have something on the device that is the cause and you will have to remove it.
If, however, it does this even when trying to start in "Safe Mode" then you are looking at hardware and it would need to be looked at by either the manufacturer, if under warranty, or a local tech.
To get into "Safe Mode" please do the following.
1. First turn off the phone.
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.