How does a dvd-rw able to be rewritten?

Which Windows was entirely (substantially?) rewritten (around 2000)?

• I have the memory of both Netscape something (Mozilla something, 6.0?), and Microsoft's Windows having been rewritten entirely (from scratch), or substantially. But which was that Windows transition? (I know that Win95 & WinNT were big steps, previously. But there was the next, too.) Having links to the news of that re-writing, is what I would like. (Links to that Mozilla rewriting-afresh efforts, valuable, too.)

• Answer:

  Microsoft ------------- • Windows 3.11 • Windows NT • Windows 95 • Windows 98 • Windows 2000 • Windows Millennium Edition (ME) • Windows 2002 (XP) • Windows Vista • Windows 7 http://en.wikipedia.org/wiki/Microsoft_Windows http://en.wikipedia.org/wiki/List_of_Microsoft_Windows_versions .