Screen frozen over regular screen

My Samsung Galaxy Tab S has a screen frozen on top of the usual screen....it will not work. I have tried to hold down the on button to turn it off...will not work. I contacted a tech guy and he told me to try holding down the on/off switch and the middle button on the bottom.....did not work as I had tried that previously. Can you help me? He said it sounds like it is time for a new one.