Why won't my Samsung Galaxy S4 turn on?

[AC Question]

My phone won't turn on for some reason. I know it's not the battery and it's the phone itself. Whenever I plug it into the computer, a charging logo appears on the screen and flashes on and off continuously. Whenever I try to enter boot mode, it won't respond and it goes back to the charging battery screen. My computer won't even recognize my phone when it's plugged in.

This is all happened when I tried to downgrade to KitKat from Lollipop using Odin. It's been acting like this ever since.

 

[the tall guy]

Hi, sounds like a user error. If you tried to root the device and it failed then that's your problem.