I understand that there are free OS's out there, but I am under the, probably false, impression that you need to know a little bit about computers to run them AND that not all games are supported on them. I use my computer as a conveyor of games, and I don't react well when I can't just install the game and play it immediately. If I have to go through more than that one simple step, then I am angry and confused and would rather not bother.
I used to revel in finding fixes, tweaking settings and putting countless hours into a game. Now... not so much. Life got busy, and if I have to work at all on my leisure time, it means that I will probably not even play that game.
So, to clarify, I believe it is the cheapest OS that will probably do what I want. If I am wrong, I am all ears.