So you "Hard Reset" (a reboot is just turning off and back on) the tablet, which wipes everything from the device, even the OS, and then allowed it reinstall itself? If that is the case, and then you redownloaded and installed any apps, then one of them would be the problem. If it is software that is at issue, then starting up the tablet in "Safe Mode" should allow for it to stay loaded and not reboot. Granted in that mode you can't access most apps, it is a restricted mode, but if it works fine in it, then you need to get rid of whatever app or item is the cause.
Now if you didn't completely reset it, as stated above, and only did the type of reset that tries to keep some of your stuff on the tablet, then that would not have removed any problem app, virus, etc. In that case you would have to do a true "Hard Reset" to get it back to what it was when it was originally made.
Now if you did do the full on "Hard Reset" and the "Safe Mode" either doesn't load or you still have the freezing in that mode, then it may well be a hardware issue and not a software one.
I am including below the info on getting into "Safe Mode" and also the correct "Hard Reset" info. Just in case you didn't do the full erase.
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.
NOTE: Doing this will clear 'all' the data on your tablet, so it is suggested you not choose this option unless you have to, or aren't worried about losing anything on the device.
Be sure you back up any data you want to keep, to a computer or cloud account, before doing the reset.
To "Hard Reset" the tablet...
1. Make sure that the tablet is actually powered off.
2. Remove your SD card, if there is one in the device.
3. Press the "Power" and the "Volume Up" buttons, together, until you see the start-up logo on the screen.
4. Once you can see the logo, release the buttons and allow the device to enter the "System Recovery Mode".
5. Next use "Volume Down" button to get to the "wipe data/factory reset" option When in recovery mode the "Volume Up" and "Volume Down" buttons are how to can navigate and highlight what option you need.
6. Once you have selected the "wipe data/factory reset", press the "Power" button to select that option.
7. On the following screen, repeatedly press the "Volume Down" button until the "Yes - delete all user data" option is what is selected.
8. Then press the "Power" button to hard reset the tablet.
9. If you took your SD card out in step 2, when the device is up and running again, reinsert the SD card.