Sounds rather odd. I mean it could be hardware, but lets start with software first. Try turning off the device (if it won't turn off you will have to wait for it to run out of power) and then start it up in "Safe Mode". Granted, in that mode you can't do a lot of things. There is a reason for that, it is restricted so that you can see if something on the device is the cause of the problem.
If it starts up fine in "Safe Mode" and doesn't freeze up at all, then I would check the tablet for bad apps, malware, viruses, etc. Any of these can cause your problem.
If, however, it still happens even when starting in "Safe Mode", then either the tablet will need a full "Hard Reset". Which will wipe everything. Or it needs to be looked at for hardware problems.
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.