I left my Samsung Galaxy Tablet 3 charging all night. Now it will not turn on. I have tried pressing volume button with the start button but nothing.
Have you tried pressing the power button for 15-30 seconds and or the power and volume and/or home button at the same time for the same amount of time? It would be better if the battery could be taken out to perform a power reset, but that would require taking the tab apart to do so, so you may have to let the battery run down, try the above suggestions again.
Try a energy test at a computer center.just like the car battery test. it will identify the problem right away ;)