When's the last time you backed up your data? Now would be a good time to back up.  Backing up simply means copying important files and folders to another drive such as a 16GB flash drive (or if you have a lot of pictures and movies, an external hard drive). Everything that needs to be backed up should all be found inside your Home Folder. (That's the folder that looks like a house). Here's what you should back up: Backup Bookmarks - Click here to see how. Documents Folder - This is where we SHOULD save our documents Desktop Folder - This is where most of us DO save our documents Library/Application Support Folder andLibrary/Preferences Folder (this is where OS X programs store your preferences like your web browser bookmarks). Movies - This is where iMovie Projects and movies and TV shows are kept. Pictures - This is where your pictures in iPhoto are kept. Music - This where your iTunes music library is kept. Downloads - (You might have this folder.) Another option is to use Time Machine. This article explains how you can set up Time Machine.