My phone ran out of battery and I put it to charge, after charging I turned on the phone... The phone shows Samsung, then the model and shuts off by itself and goes on a loop of turning off and on.

I thought it might be the battery so I bought one... Same thing happens when I installed the new battery, then if thought it might be that the phone doesn't charge so I bought a battery charger to proof that theory. I charged the batteries only to discover that the phone goes on the same loop of turning on and off by itself. Does anyone have any idea what can it be? Thank you for any help you can give me.