What's New in PowerPoint 2007
Nearly all the changes Microsoft made to PowerPoint 2007 affect the way the program looks and behaves; in other words, the changes affect how you do things in PowerPoint 2007. The most sweeping of these include:
A completely redesigned interface. The difference you notice right away is the tabbed ribbon (Figure I-2), which replaces all of the old, pre–PowerPoint 2007 menus and toolbars. Instead of wasting time trying to remember if the option you want is hiding on a toolbar or a menu or a pane or a dialog box or somewhere else entirely, in PowerPoint 2007, you reach all options from the ribbon.

Figure I-2. You can't make the ribbon larger, nor can you move it around or hide its tabs (although PowerPoint does let you hide the ribbon itself; see Section 3.2.1.2). If you're wondering why there's no File tab, it's because the Office button replaces the File menu in all Microsoft Office 2007 programs.
New file formats. The files you'll create in PowerPoint 2007 bear a different file extension than the ones you created in earlier versions of the program. The good news is that the new XML-based file formats tend to be smaller and more recoverable than the old ones. The bad news is that you can't edit PowerPoint 2007 files in an earlier version of the program unless you download and install a special converter program (Section 3.2.3 has details).
Tighter integration ...