Sorry, about being late, but you should try reading that wiki page a bit.
"Paul Allen was hired into MITS,[46] and Gates took a leave of absence from Harvard to work with Allen at MITS in Albuquerque in November 1975. They named their partnership "Micro-Soft" and had their first office located in Albuquerque.[46] Within a year, the hyphen was dropped, and on November 26, 1976, the trade name "Microsoft" was registered with the Office of the Secretary of the State of New Mexico.[46] Gates never returned to Harvard to complete his studies."
"The company moved from Albuquerque to its new home in Bellevue, Washington, on January 1, 1979.[45]"