Well Windows 10 is your go to
Some pretty old games though, they work better with Windows 7 as it was the most popular Windows version before such as CS 1.6, Dino Crisis etc
Win 10 without any doubt.
However if you don't have a good PC win10 might be a bit too weighty for your system as it require 2GB Ram only to operate the system so if you have 4 they are not enough