APP shuts down without notice...
If the APP closes itself after a few seconds of use, delete the APP, (hold your finger on the icon until they all 'wriggle' then tap the small cross which appears But ONLY on the APP you wish to delete).
Go to the APP STORE and 're-purchase' the APP and re-install it, the APP STORE will 'know' that you already purchased the APP if you are logged in to the store with the same account you bought it with. You will NOT be charged - a message will appear to say you 'already purchased and would you like to re-install?'
Yes - you would. The previous software was corrupted if it kept closing summarily.