So we know that Microsoft will be launching the next version of their operating system sometime in the next 3 years.
This article is a definitive timeline of all the releases of Microsoft’s Windows operating systems since Windows 1.0 in 1985
1985: Windows 1.0
1987: Windows 2.0
1990: Windows 3.0
April 1992: WIndows 3.1
October 1992: Windows for Workgroups 3.1
December 1993: Windows 3.11 (My first PC had windows 3.11 on it)
February 1994: Windows for Workgroups 3.11
August 1995: Windows 95
February 1996: Windows 95 Service Pack 1
June 1998: Windows 98
May 1999: Windows 98SE
February 2000: Windows 2000
June 2000: Windows ME
October 2001: Windows XP
March 2003: Windows XP 64-bit edition for Intel Itanium 2 systems
December 2003: Windows XP Media Center Edition 2003
October 2004: Windows XP Media Center Edition 2005
April 2005: Windows XP Professional x64 edition
January 2007: Windows Vista(This was the worst version of Windows ever in my opinion)
October 2009: Windows 7
So there you have it, every version of Windows that has been available to the public since 1985. Of course, there were beta versions of Windows such as Chicago, Denver, Cairo, Longhorn(which became Windows Vista), Memphis are just a few of the beta versions of the different versions of Windows that were released over the years.
These beta versions were never released to the public, only for employees of Microsoft to use.