Re: core/activation.dll not found on sims 3 launch

@gracieandholly  I need the whole dxdiag, in text form.  As in, in the screenshot you've posted, click "Save all information," save the file to your desktop, and attach it to a post.

You don't need to use a compatibility setting for Sims 3 or Origin.  The .dll file in your screenshot is a generic Origin DRM-related file which should be within the Sims 3's program files, but it's possible that your antivirus has quarantined it.  So please temporarily disable the antivirus, then repair the game in Origin: open your game library, right-click on the Sims 3 icon, and select Repair.  If that doesn't help, let me know what antivirus, if any, you use.