Like the other answers, pressing the home button thrice worked! My friend lent me his iPad and I let my cousin play the iPad. After, she left it on the drawer. I checked it and it does not work! It illuminates the screen but nothing shows up. But then I saw an answer that said to tap the screen with three fingers and it turned on "'BUT"' whenever I tap anything it squares the tapped thing. So the technique worked! I am thankful to the others who helped me since it saved me from getting grounded "'AND"' getting fined as well.