Common menus and toolbars have been replaced by the Ribbon, a strip of commands at the top of the screen that make sense only in the context of what you are doing. In Excel, for example, you’ll see commands for editing a chart only if a chart appears in your spreadsheet.
The revamp is worthwhile for anyone who got lost navigating to commands buried inside previous versions. And it’s nice to be able to preview editing changes before committing to them.
Edward Baig explains more on the USA Today site

