What is the shortest path between zero (ie no flash related development software on my computer or information about where to obtain it or get started) to running a "hello world" ActionScript?

I'm hoping for an answer that gives step by step instructions about exactly what software is needed to get started, an example of some "hello world" code, and instructions for compiling and running the code.

I've spent more time than I think should be necessary researching this question and not found much information. Hopefully this question will be found by programmers like me who want to get started with Flash/Flex/ActionScript (After my morning of researching I still don't even know what terminology to use so I'll just throw it all out there).

ActionScript tutorials I've found are focused on programming concepts, ie logic, branching, OOP, etc, and some even have code examples to download, but not a single one I've found explains how to compile and run the code. They all seem to assume you have an IDE standing by but no knowledge of programming, exactly the opposite of the position I'm in.

Here are the most related SO questions I've found:
http://stackoverflow.com/questions/59083/what-is-adobe-flex-is-it-just-flash-ii
http://stackoverflow.com/questions/554899/getting-started-with-flex-3-ui-actionscript-programming>
http://stackoverflow.com/questions/2123105/how-to-learn-flex