Windows 1.0 was the first version of Microsoft’s GUI-based operating system, released in 1985.
Like many early versions of Windows, the OS was essentially a program that ran on top of DOS. The product release didn’t actually occur until two years after the operating system was announced, leading to suggestions that Windows was vaporware and would never actually appear.
The release was a shaky start for the future tech giant, as the software itself was found to be unstable. However, the point and click interface made computers more easily usable for computer novices -- and at that time, the vast majority of users were novices, as computers were just emerging from the exclusive domain of scientists and enthusiast hobbyists.
The user-friendly nature of the Windows environment encouraged these new users who might have been intimidated by a command line interface. Windows 1.0 offered many of the common graphical user interface bits, like scroll bars and “OK” buttons.
See Steve Ballmer sell Windows 1.0 in this entertaining infomercial: