Where the Heck Do I Download the Game From?

I used to have this game on an old Windows XP laptop, and would like to get back into it, but no amount of searching reveals a single place I can download the game from. I've been through the wiki, the official forum, here, nothing, no link, no mention of where to download the game from, absolutely nothing.

I can find wikis and mentions on what versions to install, but nothing on where to actually download anything. Where is the offici8al download page for this game? And why is everyone being so bloody secretive about where to get the game?