i have an ipod touch running ios 3.1 and lately, none of teh apps on it is working. whenever i click on any downloaded app, it pretends to be opening and it crashes to the main screen instantly. i tried to delete one of the apps then went into the app store to download it again, and i got a message popping up and saying "you need to upgrade to ios 4.3 to be able to update app" is the ios 3.1 not valid anymore? i mean is teh update a must now? is this normal?