This video shows you how to keep your itunes library, music information, and song ratings intact after reinstalling your computer's operating system. Before you begin the reinstallation process, you must make sure your music is in the same location and will be in this location after the reinstallation process. After reinstalling, open itunes while holding down the shift key. In the window that pops up, click on the "choose library" button. Locate your itunes library file. This should be an "itl" file. Choose this file and click open. Now you should have all of your itunes music back, as well as song ratings, and song information.