I cannot get iTunes to play the previews of movie or shorts. After I click on 'view trailer' it pulls up the trailer but it won't play. I then click pause then play and it plays for under two seconds then quits. I installed iTunes again and it worked fine. But now it's messing up again so I installed again. Still no preview. I really don't want to completely uninstall my iTunes because there is so much on it that I don't want to lose. Anyone know how to fix this? Thanks.