I have a Samsung Galaxy 4 tablet, sm t320nu, i shut it off, turned back on and all i get is the Samsung logo, it wont turn off, wont reboot, wont factory reset, says no command with a dead android... i have tried all the videos and nothing. The TABLET WILL NOT,WILL NOT SHUT OFF, WILL NOT FACTORY RESET,WIL NOT DO ANYTHING ....
Well first you are going to have to either pull the battery (if you feel comfortable doing so) or wait for it to run out of power. Then plug it in to charge, but only for a very short while. I say that as when you try to turn it on again, you don't want to wait forever for it to run out of power should this happen again.
Once it has a little bit of a charge try turning it on normally. Should the problem occur again, then repeat the prior steps and then try starting it up in "Safe Mode" instead (instructions below). If it will start in "Safe Mode" then you likely have a virus, malware, bad app, etc., on the device that you need to remove to get it to work correctly. If it still won't start up, even in "Safe Mode", then you are looking at either a "Hard Reset" or a hardware problem.
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.