Hello, 2021 person here.
I ordered SM (Sims Medieval) back in 2012. I originally bought the game on Steam. I have 200+ hours recorded on it. At the time I played the game, I had an HP Pavillion G6 series laptop that ran on Windows 7 Vista, it's year is also 2012. I still have and use the laptop, just not for gaming (poor thing can't handle it anymore). I uninstalled and haven't played the game in years. It's been dormant in my Steam purchases for 6 years.
Last year, December, I bought an MSI computer, which runs on Windows 10. Long story short. Game didn't work on Steam client. I downloaded it from Steam, it runs on task manager but is otherwise invisible to all 5 senses. The game is a LEGAL DIGITAL purchase with the same TSM file.
After some trial and error based on what I read from other sources and this forum, this is how I got my game copy to work and function with no freezes.
Solution:
1. Went to STEAM and copied and pasted my product key into notepad for visual reference
2. Went on the Sims 3 site - https://www.thesims3.com/home.html - and created a new account under my STEAMS profile name (if I had one in the past, it's lost forever)
3. I then hovered my cursor over the "MY PAGE" tab, then the "MY ACCOUNT" tab, and then I clicked "REGISTER A GAME". Here is the link as a shortcut. https://www.thesims3.com/registeragame.html
4. I then copied my game key, SECTION BY SECTION, and inputted them SECTION BY SECTION, without the dases, into the respective spaces. The system then prompted that my Sims 3 game was registered, even though it was my SM copy.
5. Open ORIGINS game client
6. Click "MY GAME LIBRARY". You should see your copy of SM on the page. If you click on it, Origins will prompt you to update. The update is a lie. It won't work.
-I found that even when I clicked on the game within the Origin client, the file DOES NOT appear in the Origins folder. Instead, it tries to open the file that is within the STEAM folder. Use CTRL + SHIFT + ESC to find the game within the task manager and end the task.
7. Within the ORIGINS game client, right-click SM and uninstall the game. The STEAM client should open and give you a warning prompt on whether or not you want to uninstall SM from Steam. EVEN THOUGH YOU WENT THROUGH ORIGINS TO UNINSTALL. It was not a typo. Swallow your pride (200+ just...gone), uninstall the game, and remove it from your game library. You can still keep it in your downloads cache...for memories.
-I found that I had to uninstall the game "twice". From Steam first and then from my Programs and Features folder a.ka App and Features folder located in the control panel.
8. Restart your computer. I did this for good measure, just in case.
9. Re-open the ORIGINS game client and find SM
10. Click install game and complete the prompts. Wait for the download to complete. Download speed depends on your internet speed, storage space, and overall "health" of your laptop.
11. If you clicked the run after install option, the game will take a couple of seconds and then should run like normal, making your heart skip a beat because you think "oh snap, I screwed up". If you don't have the client set to run after install, close all tabs and open windows, click the new SM icon on your desktop (or wherever your game is stored), and then proceed to gush over the fact that "holy snap, it's finally working. IT"S WORKING!"
-Keep in mind, your ORIGINS game client should be up to date (your Steam one too) I have mine set to auto-update.
After that. You should do nothing but enjoy.
I hope this was helpful. I am NOT tech-savvy in the least bit. If this does not work for you I CANNOT HELP YOU, my friend. These were the exact steps I followed when I was playing around with D.I.Y solutions and eventually came up with this. I didn't call EA, the patch link that once worked is broken, and the limited information about this issue that I could find frustrated me to no end as the responses given to "fix" the issues either resulted in calling EA, buying another copy, using the patch, installing on the Sims 3 site with no in-depth step by step, or just had ranting and blame on the purchaser or company itself. I will leave my previous and current computer specs below, just in case, it helps.
Computer Specs:
Past:
http://media.flixcar.com/delivery/minisite/show/8/en/635674 (mine was windows 7)
Current:
https://storage-asset.msi.com/specSheet/us/nb/GL65%20Leopard%2010SDK-222.pdf
Happy Gaming
:)