The mystery of Microsoft's Windows version count has been solved.
Mike Nash (Microsoft Corporate VP, Windows Product Management) revealed why Windows 7 is the seventh edition of Microsoft's desktop operating system, even though many commentators pointed out that the company had released eight or nine versions of the OS.
Version 4: Windows 95
Version 4 point releases: Windows 98, 98SE, and ME (4.0.1998, 4.10.2222 and 4.90.3000, respectively).
Version 5: Windows 2000
Version 5 point releases: Windows XP (5.1)
Version 6: Windows Vista
I was surprised to realise that Windows XP (in which Microsoft unified the code bases for Windows 9x and NT/2000) was only a point release. But at least we now know how they got to Windows 7.