Essay from the year 2003 in the subject Business economics – Miscellaneous, grade: 2, University of Abertay Dundee (Economics Department), course: Industrial Organization, language: English, abstract: You are using a PC? Probably there is a version of Microsoft’s Windows operating system running on it. When Microsoft, nowadays with 90% market share the worlds leading operating system producer [Eisenach/Lenard, 2001], years ago started to develop and to distribute Windows the company applied for a worldwide copyright. Which allows them to be the only supplier of this particular software. Therefore Microsoft is a monopoly in the Windows-market and might be one in the whole operating system market. But Microsoft is more than this. They are also producing completing application programs and tools for the Internet. Question is now whether Microsoft is abusing its market power or not. And how this behaviour might affect consumers. This essay is going to outline how their operating system monopoly arose and if this power is transferred into adjacent markets. It will be tried to be both critically and descriptive with a final statement at the end.