Samsung Galaxy S3 keeps restarting, stuck on Samsung logo Two days ago I got the official update of jelly bean 4.3 to my Samsung Galaxy S3. Last night phone was dropped from a small height. Today morning when I switched on the phone it worked fine. But in the evening, suddenly my phone restarted and goes to Samsung Logo Splash Screen (Samsung galaxy S3 GT-I9300T) and keeps rebooting. I removed the battery and insert it after a few second. After that the phone worked fine and again the same problem happened.

If I remove the battery to switch off the phone and if I insert the battery again, phone switch on by itself (without press power button) and keep restarting. 

I try to open the Home + Volume Up+ Power On button option. But is not working. If I plug the phone to charge, gray battery shows and again restarting to charge. (I mean, phone won’t stay in a stage).

If i try Home + Voulme Down + Power On option, phone shows the download mode for 5 seconds and restarts again. 

So can you please let me know it’s a software problem or hardware problem? 
If it’s a software how to fix it ? ( I tried the emergency firmware recovery through kies, but kies couldn’t fine my phone).

My phone current status video below 
https://www.dropbox.com/s/xvq6bd93qjmdt6o/20131012_235047.mp4

Note : I downloaded the video from youtube, because I wanted to show the current situation. ( But my phone is critical than what is shown in the video)

Thank You.
It does look like a stuck power button. (as ridiculous as it may sound)

The behaviour in your phone is exactly as it is when I press and hold on my power button for an extended period.

By right, the device should not turn on by itself when the battery is inserted. It should remain turned off - only a hardware switch can turn it on. As your phone turns on by itself, it clearly shows that the power button is being pressed.

Furthermore, the power menu shows when you turn the phone on without touching the phone at all and again showing the power button being pressed.

I suggest you bring your phone down to someone who knows how to open up your phone to see if there has been any damage to the power button.