@LeHippieMon Windows 10 shouldn't be a problem.
Please, don't create a new account, that won't fix this issue as you can't even log into the launcher and you wouldn't have your games in your new account.
Try to do this:
- Close the launcher completely (check it's not minimized near the clock)
- Go to Documents \ Electronic Arts
- Rename 'The Sims 3' folder to 'The Sims 3 old'
- Open the launcher again from Origin.
Is the issue still there? Does it happen if you try to open the game without logging in?
-Mai