1981

Bill Gates and Paul Allen.

The first IBM PC ships, loaded with Microsoft's operating system and using Microsoft's BASIC compiler as its programming language. It doesn't come with any software; these days, people write their own. The D in DOS now stands for disk instead of dirty.

Microsoft incorporates.

The Rolling Stones release Tattoo You, containing a ditty called "Start Me Up." Some 14 years later, Microsoft brass give the Stones $2 million for the right to use the song in their Windows 95 ads. The lines "My eyes dilate/my lips go green/my hands are greasy/she's a mean, mean machine" are mysteriously omitted.

1982
Compaq creates the first "IBM clone" and the first portable PC: a hefty device that runs a 4.77-MHz Intel 8088 processor. By the 1990s, Windows and Intel will replace IBM as the driving forces in developing the PC.

Microsoft receives an early prototype of the Macintosh from Apple and gets some practice writing graphical interfaces by developing software for the new machine. Ultimately, Microsoft would produce a set of desktop utilities for Apple computers, including its alarm clock and calculator.

At the big computer trade show Comdex in Las Vegas, VisiCorp shows prototypes of a windowing graphical user interface that runs on top of DOS. Bill Gates sits through three back-to-back demonstrations. He flies in other Microsoft officials to watch, then hightails it back to Washington to work on plans for his own graphical overlay for DOS.