Windows Vista is Microsoft's most important software release in more than a decade. It offers users an abundance of new and upgraded features that were more than five years in the making: a gorgeous, glass-like visual overhaul; superior searching and organization tools; a multimedia and collaboration suite; and above all, a massive, top-to-bottom security-shield overhaul. There's scarcely a single feature of the older versions of Windows that hasn't been tweaked, overhauled, or replaced entirely. But when users first encounter this beautiful new operating system, there's gonna be a whole lotta head-scratchin', starting with trying to figure out which of the five versions of Vista is installed on the PC (Home, Premium, Business, Enterprise, Ultimate)....