Microsoft's long-promised upgrade to its Windows operating system, Vista, offers a new look, more user-friendly features and new security fortifications that protect the operating system and reduce Internet browsing risks. Vista is available in five versions, from the stripped-down Home Basic version, which sells for about $100, to Vista Ultimate, which sells for $400.

The new look includes menus and windows that cast subtle shadows. Among the new features is a powerful Instant Search tool, which can find files, folders and e-mail messages that contain the search phrase.

To help you determine whether an older computer is compatible with Vista, Microsoft offers an Upgrade Advisor available at Additional computer memory and other upgrades may be required. In some cases, it may be cheaper to buy a new computer with Vista installed than to upgrade.

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