Microsoft was started by Bill Gates (in fact he dropped out of college to start it).
he happened to have 12 lawyer buddies who funded his company at the begginning in the form of buying stock like there is no tomorrow. IBM almost immediately licensed him to create IBM-DOS, the first operating system ever. however in their foolish business failure the contract was not exclusive so Bill Gates turned around and sold and identical version named MS-DOS to all the IBM clone companies sitting in the wings. then xerox invented the mouse and they GUI which Apple bought from them. then Bill Gates decides to slap a GUI on top of MS-DOS and born was windows.
NOTE: even now windows XP is still nothing but a GUI running off DOS
another NOTE: I just woke up so I probably misspelled everything, so xkuse teh axidentil mizpelingz