You can try starting it up in "Safe Mode" and see if it will load. While you get limited access in that mode, if it will start up then you know there is something on the device you need to remove. Virus, malware, bad app, etc. If it won't start up, even in that mode, then it is probably a hardware issue.
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.