When you are working on a PowerPoint presentation, the AutoSave option, if enabled, automatically saves your file at the specified time increments. This way you get to replace your current file with an earlier version. This can be very useful if you want to go back to the state of your slides an hour ago, or even two hours ago without having to use any Undo option.
Learn how to restore earlier versions of your current presentation in PowerPoint 2010 for Windows.

