Windows XP

From Conservapedia

Windows XP is the penultimate significant release of the Microsoft Windows operating system, and was made available on October 25, 2001. "XP" stands for eXPerience.

Windows XP has been criticized for poor performance, significant security vulnerabilities, and poor DOS backwards compatibility, among others. Interestingly, when Windows Vista debuted, many organizations chose to retain XP in favor of the newer system, as it was perceived of as being of higher quality.