@Meli_ZG It still seems like a permissions issue. When you made the new user account, did its username have any letters with accents, or other characters that English doesn't use? Right now, Origin isn't handling certain characters well—I've seen examples from Croation as well as Polish, German, and Scandanavian languages. Having a file path (This PC\Users\username\Documents...) to your saves that includes a letter Origin or Sims 3 doesn't recognize could account for the issue you're describing.
This dxdiag also has a few errors related to a Windows language package, although no new ones since the first dxdiag. I'm not sure what to do with those though, and if you're not seeing any issues on-screen, it might not be a real problem.
If that's not it, try disabling Origin in-game. Hover over your username, select Application Settings, then Origin in-game, and disable the setting. Also try running both Origin and Sims 3 as an admin: right-click on the Origin shortcut and select "Run as administrator." Once you're signed in, you can do the same for TS3.exe, which by default is located in:
Program files (x86)\Origin Games\The Sims 3\Game\Bin
