Tastatura - 2:16 pm on Oct 16, 2008 (gmt 0)

numbering scheme goes like this: there were three versions of the original Windows, with NT dubbed 3.1. Then came 95 as version 4, with 98, 98SE, and ME all considered minor updates. 2000 got the next major update to 5, while XP is 5.1, Vista is 6, and this new one is labeled 7. The confusing bit is that it's actually numbered 6.1 internally, a minor version change for the sake of application compatibility.

How does MS number thy Windows? [engadget.com]

From Ms : Why 7 [windowsvistablog.com]