Windows XP, Microsoft's next operating system, is shaping up as one of the most exciting--and controversial--products ever put out by the Redmond, Washington, technology behemoth.

The controversy over the OS formerly code-named Whistler, and now in Beta version 2, stems from Windows Product Activation, a new and stringent copy protection scheme that requires upgrade customers to contact Microsoft for an ID number (a procedure separate from the usual registration process). This feature, which could hinder some installations, isn't the only potential upgrade hurdle. Microsoft already anticipates that XP may conflict with some system BIOSs, hardware, and applications. As a result, installing the new OS could be a real hassle for people who don't have state-of-the-art PCs. You'll also need a gigabyte of free disk space.

However, Windows XP inherits Windows 2000's stability and security, and it will be even more appealing than Windows Millennium Edition to digital photo, video, and audio enthusiasts. XP also includes Me's highly popular software for returning a system to the way it was before installation of a buggy driver or application.