Iphone 4s has vertical lines all across the screen and will not power down unless it is charging. What is the problem here?

My iphone 4s recently stopped turning on. I left it alone on the charger for a few days and now will power on just fine. However I have vertical lines going across the entire screen. I also noticed that it will not power down and stay off unless it is connected to the charger. Is this a hardware problem?