History of Microsoft Windows
Microsoft announced the first version of Windows in 1983, but strangely it wasn't introduced until 1985. Windows 1.01 was basically just a suped-up MS-DOS shell.
Next Microsoft introduced Windows 2.03 in 1987. Enhancments included: resizable/overlapping windows and an enhanced window control system.
Next came Windows 3.0, this was the first version to use the Program Manager. Windows 3.1 and 3.11 were basically the same OS