Currently Being ModeratedJul 7, 2013 2:40 PM (in response to benibacon)
Closing apps typically indicates that the app is crashing.
You might try restoring your iPad by plugging it in to iTunes (latest version: 11.0.4). Let it sync, then choose "Restore ..." from the iPad's summary page in iTunes.
You may wish to be selective in which apps you restore to the iPad, as one or more may be corrupt.