why wont my ipod 5 stay turned on?

I tried reseting my ipod touch 5 multiple times and my lock screen would pop up for about 2 seconds and then the screen would go black. Ive had it for almost two years and it was random. Right before this happened when I tried to unlock my ipod it wouldn't let me. a little box went around the clock and the slide to unlock. when I tried to change the accessibility when you tap the home button 3 times it put a little square box around what I clicked on. What do I do?