You will need DOS to run turbo, not MS DOS mode or command prompt in Win98/95/2000/XP, real good ol' DOS. If you have an old win95/98 box, you can simply keep pressing F8 at startup, about the time you press del to enter bios, and at the menu that comes up select command prompt only. This will give you DOS and not much else. Start turbo and away you go, probably best off pressing F8 which brings up the jog screen, and use that.
Either that or download Mach and install that, I haven't used it so I can't give any advice on it, but I'm sure someone will post something here.