If you have existing slides that have reusable content, you can import them into any new presentations you create. I reiterate that you must first create and import an outline so that you have a structured presentation in place — thereafter do use the Reuse slides option to add more slides or even replace existing ones. Finally you can add any new slides that you need to create from scratch.
Learn how you can reuse existing slides in PowerPoint 2007 for Windows.

