DOS is still alive and kicking. Well, sort of

http://www.freedos.org/

Comes in 8Mb and 153Mb download versions and a thing called "Balder" that fits on a 1.44Mb floppy.

The source code is also available.

[My wife bought a new kitchen, so I have been rather busy these past few days, and haven't had a chance to play with it].

if a Black screen and white text is a hacker screen then many will believe that..
Better not let anyone see my black screen with green text then (DOS v.3.3)

IIRC Windows ME was the last OS that was DOS based. I also seem to recall that whilst NT wasn't DOS based, it ran some sort of virtual DOS machine?