I stupidly installed an Itunes update yesterday and now when I try to open ITunes, I get this 'Updating Itunes Library' message and when it scrolls to the end after about 5 minutes of waiting, it automatically shuts Itunes down! It's happened about 8 times now, even after re-booting. I have no idea what to do about it, and I have $3,000 worth of music in my library! WHAT DO I DO????