Much of the recent buzz in the computer world has been about the release of Microsoft Windows Vista, the replacement for Windows XP. It is a significant move forward for the Windows platform, which has been more or less stable (joke intended) for the last eight years.

Your first choice when upgrading (or buying a new PC) is which version to pick. Under XP it was rather simple: home users picked "XP Home," and business or higher-end users selected "XP Professional."

With Vista, of course, the world is more confusing. At the bottom end is "Vista Home Basic," which should be selected if you have an older PC and a built-in graphics card (i.e., not one separate from your motherboard). If you use your PC just to browse the Web and read e-mail, this is your version.

Next up is "Vista Home Premium" which adds the elegant "Aero" interface if you have the graphics chops to pull it off. This is the version for most users of Windows — the sweet spot of performance and price. It should be the only choice for laptop users because it adds the Windows Mobility features and support for tablet PCs. It also has the Windows Media Center options to interface with your television.

Next up is "Windows Vista Business," which offers the same rough features as "Premium" but adds a complete backup-and-restore system, remote desktop capability and Windows Movie Maker software.

The high-end user will want "Windows Vista Ultimate," of course. This has everything built in, including BitLocker hard-drive encryption.

If you have Windows XP already, just buy the upgrade versions, which are cheaper.

What should you do before you begin installation?

Read this sentence twice: Back up your data.

Installing an operating system upgrade is not simple. The entire computing guts of your system are being replaced and updated. Things can and will go wrong, which could make your PC unbootable. Do not risk losing your family photos, wedding pictures and master's thesis. Copy everything you want to your CD or DVD burner if nothing else. Just make a backup.

The Vista Web site (www.microsoft.com/vista/) will share the complete system requirements, but the goal should be to experience Aero, which brings with it a rather stunning level of graphics for an operating system. The PC to run it will be hefty: a 1 gig processor or more, 1 gig of system memory, a graphics card with at least 128 MB of video memory on board and a DVD-ROM drive. (Vista ships on a DVD.)