All data (pictures, portfolios, music, documents, etc.) are stored on your hard drive. Your hard drive is a machine that has physical parts that move, and just like any other machine, those parts can stop moving. If your hard drive stops working, there is little chance of easily retrieving anything that you had saved. We strongly recommend that you purchase an external hard drive and use Time Machine to back up your computer on a regular basis. Nothing is more heartbreaking than losing everything when you have to replace your failed hard drive!