durango
The codename for windows 8 is "Blue".
Windows 8/9 is a codename for Windows 7's "successor". Apparently Windows 8/9 has been actually in development for awhile now. Microsoft actually has a presentation about windows 8
Whistler.
Longhorn
Windows 2000 was codenamed Utopia. It just isn't known publicly for some odd reason.
The code names "Vienna" and "Blackcomb" were both given to Windows 7.
Whistler.
Windows NT 4 did not have a specific codename. The changes between it and Windows NT 3.51 (codenamed Daytona) were mainly just a shell update. The shell update was created as part of the Cairo project.
Windows vista was introduced in July 22, 2005. It is known by its codename 'longhorn' .
The codename for Windows 1.0 was "Interface Manager." Released by Microsoft in November 1985, it was the company's first graphical user interface for MS-DOS, allowing users to interact with their computers through windows and icons rather than just command-line inputs. The name was later changed to Windows to reflect its core functionality.
It think was Longhorn
Windows Seven is the codename for the next version of Windows in development by Microsoft. As yet, Microsoft have refused to give details of the operating system, as they are currently busy marketing Windows Vista, the current version of Windows.