Welcome to the forum.
Have you used the reset (little hole on the right side of the tablet) function?
If that doesn't work you could try a cold boot/hard reset.
"Unplug the power cord and shut the unit off. Press and hold the VOL DOWN and then POWER button at the same time for at least 10-12 seconds until after the start-up screen appears and is joined by some small print at the top of the screen then let them both go. If the TF booted the way it always does, you have not accomplished the task,try again until you have seen the 2 icons in the screen.
After a few seconds you should see a couple of shapes in the middle of the screen called "Wipe Data" and "Android". The right "Android" will have a green highlight fading in and out. Wait a few more seconds until the term "Cold Booting Linux" appears in the list near the top of the screens and let it reboot. If you own a keyboard dock be sure you do this with the dock connected.
This applies to all TF models, however, if your Prime is locked up, there is a reset available using the hole just below the SD Card slot, this is NOT the same as a hard reset."