Using VMWare and an unknown amount of time, an individual chose to install MS-DOS 5.0, Windows 1.0, Windows 2.0, Windows 3.0, Windows 3.1, Windows 95, Windows 98, Windows 98 SE, Windows 2000, Windows XP, Windows Vista, and Windows 7. Fortunately, he recorded the process for us to gain some observations regarding the trend in Windows upgrade process and backwards compatibility (or lack thereof in some instances).
No love for Windows ME…
If that wasn’t a virtual disk, it would need some serious defragging.