If you have already tried clearing safari catch, cookies etc, soft restart, quitting all apps in app switcher, hold down power button until red slider appears and then hold down the home button until it goes back to homescreen. If it still gives you issues your hard disk could be almost full. Most people are silly enough to blow money on 16 gb pads. When you consider that some of these apps are pushing 2gb and a 16 gb ipad only has about 14 gb of actual storage available, it's pretty simple math your pad can't hold jack! For globs sake people if you've managed to save enough for an iPad do yourself a huge favor and save up enough for a 64 gb model. You will not regret it.