Windows Vista, also known as “Windows NT 6.0” or just “Windows 6”.
With this version of Windows, Microsoft has made some very radical changes to how things look and work. Gone are the old Explorer interface, Display Properties, and many other things.
Besides changing how a lot of things look, Vista introduces new “always on” features that run in the background, potentially making the OS run better for many people. Things like disk indexing (Windows Search – which catalogs things for quicker searches), Disk Defragmenter (re-arrange files and programs for quicker access), and Superfetch (pre-load and keep your most commonly ran programs in memory) will run on their own without the user having to do anything.