If you work with multiple open windows, you should be using Flip or Flip 3D to move among them. Perhaps you have iTunes running and playing music, you're surfing the Web in Internet Explorer, you're checking your mail with Microsoft Outlook, and you're working on a document, all at the same time. With this many programs open, it's cumbersome to move among them effectively. There are ways though, including Flip and Flip 3D.
If you've never seen Flip 3D, check it out. Windows Flip 3D offers a novel way to access and move among open windows and is used in conjunction with the Aero interface. (You can't use Flip 3D if your computer does not support Windows Aero.)

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Before you can use Flip 3D you need to enable Aero on Windows Vista (it's enabled in Windows 7):
1. Right-click an empty area of the desktop, and click Personalize.
2. Click Windows Color and Appearance.
3. If you're currently using Windows Vista Basic, you'll see the Appearance Settings dialog box.] If you're currently using Windows Aero, you'll see the Aero options, where you can select a different color scheme, enable transparency, make changes to the color intensity, or show the color mixer. If you see the former, choose Windows Aero. If you see the latter, configure Aero as desired.
4. Click OK to close the window.