From 20 November 1985, here's the first Windows boot screen featuring the old Microsoft logo. Key fact: you couldn't overlap windows in this version - they were all tiled. Interestingly, Microsoft still supported Windows 1.0 until the end of December 2001. Seriously.
While an earlier version (2.03) emerged in 1987, it wasn't until 1988 that Windows 2.1 properly arrived, in the form of the 286 and 386 versions. The not-so-different boot screen also features the new Microsoft logo. The first versions of Word and Excel ran on Windows 2.0. You could also overlap windows. Which was good.
Into the nineties and Windows 3.0 shows plenty of signs of graphical improvement - indeed the graphics were much improved from 2.x. The MS-DOS Executive file manager was replaced with the Program Manager (which remained a feature of Windows 3.1).
The first version to include Minesweeper, Windows 3.1 (codenamed Janus) was released in 1992 and contained advanced personalisation and featured 32-bit disk access. It also introduced the Windows flag to the boot screen for the first time.
Windows for Workgroups 3.11
Windows for Workgroups saw the light of day in October 1992 and featured native network support and sharing. It was an essential for business back in the early nineties. I don't know about you, but these boot screens look almost like a step back from Windows 3.0!
Introducing the clouds! Windows 95 (codenamed Chicago) was a great leap forward in terms of productivity and introduced THE INTERNET, albeit in limited fashion. It was seriously better looking than earlier versions of Windows and was seriously successful as a result. It laid the graphical foundations (if not the codebase) for the Windows we still use today.
1996's Windows NT became a staple of companies worldwide until it was replaced by the mighty Windows 2000. From memory, it really wasn't that stable, but had great security features.
June 1998 saw the release of Windows 98, an OS with a surprising number of users even today. Continuing the clouds theme from Windows 95, Windows 98 introduced improved USB support through the 1999 Second Edition and ushered in the Windows Driver Model.
Truly a version of Windows to look back on with fondness. Like NT, Windows 2000 has a long industrial legacy. Though you'll find Windows XP running most businesses today, Windows 2000 is still used widely.
So you thought Windows Vista filled you with anger? You obviously didn't use Windows ME, an operating system that emerged in 2000. It included several improvements from Windows 2000 but otherwise it was rubbish - like its boot screen.
2001's Windows XP (codenamed Whistler) brought improved security and robustness by moving across to the NT codebase, incorporating huge driver support and releasing both Home and Professional editions. In 2006, IDC believed there were over 400 million copies in use.
Yeah, it's interesting isn't it? God knows what Microsoft was thinking, but it only succeeded in making this crap-looking and basic screen. It probably wanted to save on boot-up time or something.
Windows 7 introduces this animation, which appears before the log-in screen, but once again there's no boot screen in the traditional sense. But it does look really quite nice, as does Windows 7 itself.