I have uninstalled several applications. After shutting down my MacBook and then starting it up, there are 3 question marks on the dock where the apps would be. I know how to get rid of them (One way is to right click and then remove from dock. Another is to move to the desktop. Both ways result in a "poof" and they are gone.) But after shutting down and starting up again, the question marks are there again. Please help!