Error Code 16, corrupted saves

lilmissbrouge188​  Making a new Windows account doesn't delete your old one and therefore doesn't delete your existing files.  So you don't technically need to back anything up; that part of the guide was for when people change OneDrive settings.  Here's how to create a new account:

https://support.microsoft.com/en-us/windows/manage-user-accounts-in-windows-104dc19f-6430-4b49-6a2b-e4dbd1dcdf32

Follow the instructions under Add a user account, making sure you do NOT add an email address or any details about a Microsoft account; this will make the new account local.  Then configure that user as an admin, as described in the last section of that guide.

Then login to that account and try to play Sims 3, and let me know whether it works.  We can go from there either way.