windows 3.x was a family of microsoft windows operating system, released in 1990-1994. notable operating systems in this family include windows 3.0 and windows 3.1. this windows could run in either standard or 386 enhanced memory modes. both of the modes used a graphical user interface (or picture-based), and supported a mouse, but 386 enhanced mode was faster and was better at multitasking (or doing many things at once). windows nt 3.x was released in 1993-1996.