1. Windows 1.01
Release: 20.11.1985
2. Windows 2.03
Release: 01.11.1987
3. Windows 3.0
Release: 22.05.1990
4. Windows 3.1
Release: 19.03.1992
5. Windows NT 3.1
Release: 27.07.1993
6. Windows NT 3.1 Advanced Server
Release: 27.07.1993
7. Windows For Workgroups 3.11
Release: 01.11.1993
8. Windows NT Server 3.5
Release: 21.09.1994
9. Windows NT Workstation 3.5
Release: 21.09.1994
10. Windows NT Server 3.51
Release: 30.05.1995
11. Windows NT Workstation 3.51
Release: 30.05.1995
12. Windows 95
Release: 24.08.1995
13. Windows NT Server 4.0
Release: 24.08.1996
14. Windows NT Workstation 4.0
Release: 24.08.1996
15. Windows 98
Release: 25.06.1998
16. Windows 98 SE
Release: 05.05.1999
17. Windows 2000 Professional
Release: 17.02.2000
18. Windows 2000 Server
Release: 17.02.2000
19. Windows ME
Release: 14.09.2000
20. Windows XP Home
Release: 25.10.2001
21. Windows XP 64-bit Edition
Release: 25.10.2001
22. Windows XP Professional
Release: 25.10.2001
23. Windows Server 2003
Release: 24.04.2003
24. Windows XP SP2
Release: 06.08.2004
25. Windows Vista
Release: 30.01.2007
26. Windows 7
Release: 22.10.2009
Source: Wikipedia
Release: 20.11.1985
2. Windows 2.03
Release: 01.11.1987
Release: 22.05.1990
4. Windows 3.1
Release: 19.03.1992
5. Windows NT 3.1
Release: 27.07.1993
6. Windows NT 3.1 Advanced Server
Release: 27.07.1993
7. Windows For Workgroups 3.11
Release: 01.11.1993
8. Windows NT Server 3.5
Release: 21.09.1994
9. Windows NT Workstation 3.5
Release: 21.09.1994
10. Windows NT Server 3.51
Release: 30.05.1995
11. Windows NT Workstation 3.51
Release: 30.05.1995
12. Windows 95
Release: 24.08.1995
13. Windows NT Server 4.0
Release: 24.08.1996
14. Windows NT Workstation 4.0
Release: 24.08.1996
15. Windows 98
Release: 25.06.1998
16. Windows 98 SE
Release: 05.05.1999
17. Windows 2000 Professional
Release: 17.02.2000
18. Windows 2000 Server
Release: 17.02.2000
19. Windows ME
Release: 14.09.2000
20. Windows XP Home
Release: 25.10.2001
21. Windows XP 64-bit Edition
Release: 25.10.2001
22. Windows XP Professional
Release: 25.10.2001
23. Windows Server 2003
Release: 24.04.2003
24. Windows XP SP2
Release: 06.08.2004
25. Windows Vista
Release: 30.01.2007
26. Windows 7
Release: 22.10.2009
Source: Wikipedia