Microsoftsoftware company. The Managing Director is Bill Gates. Microsoft is most well known for creating Windows and Internet Explorer.
Microsoft was called a monopoly by the United States Justice Department, and by some people and companies who compete with it. A complaint against them is that they are always changing their operating system so that only their own applications reliably work on it. Another complaint is that they include some of their own applications with Windows, like Internet Explorer, which makes it harder for other software makers to compete.
One of Microsoft's licenses is called shared source. Software source code which is under a shared source license can only be viewed by certain people. Students who have an opportunity to view shared source code software cannot modify the source code. Open source is different because it allows people to change the software, or use the source code in other applications. Microsoft claims that open source and free software are like Communism. Some people believe this is propaganda, but others believe Microsoft's claims - which are spread by their advertising.