The reason Microsoft has to pay the fine is that they did not want to disclose necessary information about their operating system that companys would need to build competitive and better products.
Imagine you want to create a website but you do not know how HTML works because W3C does not give you that information. But you can of course buy their shiny new WYSIWYG editor. But hey, this is a free market economy isn't it? No problem with that. And of course you can still try to figure out how it works somehow by looking at the source code of websites. Just will take a little longer doing it by trial and error.
For building a simple application like notepad you do not need detailed information about the operating system.
You are paying for the Internet Explorer and for the Media Player with every license of Windows you buy. Where do you think the money for the IE and Mediaplayer programmers comes from? The Bill Gates charity fund?