My apps keep closing out.

To fix this, download and install any free app (you can delete it later).

Try going to Settings>iTunes & App Stores, tap the Apple ID at the top, sign out, then sign back in. If it still isn't working then you'll have to try restoring. You won't lose everything if you take the proper precautions first, which include:

1. Sync with iTunes to create a new backup (unless you're backing up to iCloud) and transfer your purchases to your iTunes library. If you're backing up to iCloud do a manual backup in iTunes by right-clicking on the name of your phone on the left side and selecting Back Up.
2. Import your photos and videos to your computer (see http://support.apple.com/kb/HT4083)
3. Back up your contacts separately (such as by syncing them with iCloud or to a supported program on your computer)

Then go to the Summary Tab of your iTunes sync settings and click on Restore. At the end, restore to the iTunes backup you made at step 1.

Sorry you continue to have problems. At this point you may want to make an appointment at the genius bar at a nearby Apple store to have it looked at. Be sure it's backed up before going in case it has to be replaced.

You have to check your memory. If it says 0 bytes you may have to delete a couple songs that you dont really want or a a lot of photos to free up your phone.

Go to: Settings>General>Usage. Then see how many bytes of free memory there is.

Thing is even if you delete a couple it may not pop up and put it saying that you have free bytes but just know that as long as you delete some stuff to make room there should be that much room. Deleting apps doesnt really work that well but photos and songs work a lot better.

Go to Settings\General\Background App Refresh\Background App Refresh>Off

i hope this helps. It works for me.

have a nice day!