With your iPad on, go to the home screen (the screen that shows you all of your apps). Then double tap your home button (the circular button on the face of the iPad, with the picture of a square on it). This should bring up your active (but idle) apps, on a menu bar, along the bottom of your screen. Put your finger down on one of the apps, and hold it there, until your the icons begin to wiggle, and you will see a small red circle, with a white dash, in corner of the app icons. Tap each of the icons, on the red circle, to close them out. When you have closed all of your active apps, click your home button once, to return to the normal iPad screen. Now try to open the programs you haven't been able to use.
• This may not work, but I have had apps (like the TV guide app) stop opening, and this has solved the issue.
• If you hold your finger down, over an app icon in the normal iPad window, you will activate the window editing for the screen. It's similar to what is explained above, except if you tap the circle (which will be black, instead of red, with a white "X"), it will unload that app from your iPad. You may then reinstall it from the App store (no charge).