For all practical purposes, Windows 3.0 and the subsequent 3.x releases were the first computer operating systems most people used. Microsoft had Windows 1.0 released in the early 1980s, billing it as the first interface for the “serious PC user,” and even before the era of graphical user interfaces had a text-based system that introduced users for the first time to that seldom-used “backslash” key for the first time, but those were more niche and business-oriented products. As personal computers began to penetrate the family market, they were mostly pre-installed with Windows.

On this day, May 22, in 1990, Windows released version 3.0 of their interface program. With an eye on the “personal,” as opposed to business, the new Windows included games like Solitaire, Hearts, and Minesweeper. Early advertisements for it suggested “Now you can use the incredible power of Windows 3.0 to goof off.”

To encourage software developers to create more Windows-compatible programs, Microsoft released a software development kit (SDK), giving outside developers an opportunity to write Windows-compatible programs and saving their own engineers time from having to write drivers. The wide variety of Windows programs made by those outside developers no doubt contributed to its great success.