Not as much as some would believe. The change from NT 5.x to NT 6.0 (Vista) wasn't really a rewrite in any sense of the word, at least no more than Linux 4.0 is

Not as much as some would believe. The change from NT 5.x to NT 6.0 (Vista) wasn't really a rewrite in any sense of the word, at least no more than Linux 4.0 is a "rewrite" compared to 3.0, despite that all the little chunks had been touched over eventually. Many applications (such as Notepad and Paint) derive directly from the original Windows 1.0 versions.