A cikin 1975, a Albuquerque, New Mexico, Allen da Gates sun fara sayar da fassarar harshen shirye-shiryen BASIC. Allen ya zo da sunan asali na "Micro-Soft" (haɗin "microcomputer" da "software"), a cewar wani labarin mujallar Fortune na 1995. A cikin 1980, bayan da Microsoft ya yi niyyar isar da IBM tsarin aiki na faifai (DOS) don asalin IBM PC, kodayake ba su ci gaba ba tukuna, Allen ya jagoranci yarjejeniyar da Microsoft ta sayi QDOS (Quick and Dirty Operating System), wanda Tim Paterson ya rubuta, wanda, a lokacin, ya yi aiki a Seattle Computer Products. A sakamakon wannan ma'amala, Microsoft ya sami damar kulla yarjejeniyar samar da DOS wanda a ƙarshe zai gudana a kan layin kwangilar IBM na PC. Wannan ya tabbatar da maɓallin ruwa a cikin tarihin Microsoft wanda ya kai ga Allen da Gates.
Kamfanin Microsoft