Microsoft is one of the largest and most influential companies in the computing industry. They cover many areas of computing, mainly operating systems. Below are various links to useful pages that deal with the Microsoft Windows operating system.
Linux is a freely-distributable open source operating system that runs on a number of hardware platforms. There are many versions of linux created by different companies as you can freely edit the system (open source). Below are useful links to the SUSE Linux site.
Apple is one of the most influencial companies within the computer industry today. They produce a wide variety of programs but also specialise in operating systems. Below are various useful links for Apple users.