Hello,
@gmarmont , I'm afraid you are unable to get a digital copy of Sims 2 for Windows OS. The giveaway and ability to purchase Sims 2 digitally on Origin ended October 2018. If you check the dates on many of the threads and posts saying the game is available for free or digital download, they are likely dated before October 2018. Here is the link from EA explaining the ending of the sale and giveaway for Sims 2. https://answers.ea.com/t5/Other-The-Sims-Games/Ending-code-support-for-The-Sims-2-Ultimate-Collection/m-p/7101525#M15431
Your best bet to be able to play the game is to find a new or used copy of Sims 2 Base game on disk. You can purchase them from Amazon, E-Bay, local game stores that sell used copies of games or thrift stores. Don't worry that it's a used copy because the codes are no longer used to register the game. If your computer does not have a disk drive, you will also need to purchase one of those as well. The game does run on Windows 10, but will require some extra steps to get it to run.
