Screen won’t turn on.

My ps vita will charge and turn on and display a blue light, but the screen is black, I have watched videos on how to reset, they all say that I should hold the power button to reset, however when I do that it simply turns the device off with blue flashing light, I have also tried all the button combinations required to “hard reset the device”, none of them seem to work, I am completely stuck as to what to do. Thanks.