Flip Ultra hd wont turn on just got it today?

my flip wont turn on i got it today but when it came it was hot so i thaught that was normal so i read the instructions what to do i put the battery right just like the instructions said so i tried turning it on but nothing it didnt turn on i also tryed with diffent batteries it still didnt work i tryed charging it on the computer but the light doesnt show up it charging and it still doesnt turn on please help