There is no operating system by the name of Windows 2007. However, Microsoft released a new version of Windows, called Vista, in 2007. Some of its features are Windows Aero, improved file search and Windows Sidebar.
Windows Aero is the name given to the visual parts of the operating system. Aero features translucency, glass effects, interface animations and previews for open applications. By default, Vista displays the title bar and the frame of a window in translucent colors. The operating system then applies a glass effect that simulates light reflection on the translucent parts. Users can adjust translucency amount or turn the feature off completely.
Aero also allows users to peak into open applications without switching to them. When the user hovers the cursor over an application on the taskbar, Windows Vista displays a small snapshot of the application. Likewise, pressing Windows+Tab or Alt+Tab to switch between applications shows live previews for each application.
Windows Vista also features additional functionality for the search tool. The operating system constantly prepares file indexes to make sure searches take little time. Moreover, the results are displayed with thumbnails that show the contents of each file to help the user identify the file he's looking for.
Windows Sidebar displays real-time information through gadgets. There are gadgets available for news headlines, weather forecast, hardware monitors, note-taking applications and more. The operating system ships with 11 gadgets but more is available online.