How Do I Shut My Kindle Paperwhite Down After 40 Seconds?

My Kindle Paperwhite is less that 2 years old and not used often. Suddenly iIt does not function at all, although it might be charged and regularly updated. I tried holding down the start button for more than 40 seconds. I tried different ways of charging the battery. I took it to Incredible Connection, but they referred me to you. It only shows 3 screens: white, one with the tree and one with a battery needing to be charged.