Windows XP was one of Microsoft's greatest successes and greatest failures: A success because it was so rock-solid, a failure because it was so good that many people didn't want to upgrade to Windows Vista. Based on initial looks at Windows 8, Windows 7 may well be the new XP.
Windows XP was first released in 2001, and because of its speed, stability, and simplicity, has been a winner ever since. Even though it's going on 11 years old, it's still the most popular version of Windows
according to Net Applications, with a 44.85 percent market share as of May 2012, compared to 40.51 percent for Windows 7 and 6.88 percent for Windows Vista.