Maxine224 What antivirus do you use, and does it help to (temporarily) disable it? You could do so just long enough to repair Sims 4 and try to launch it; as long as you didn't do anything else at the same time, your computer should be safe.
If that doesn't help, please let me know whether the game is installed on an internal or external drive, and if external, how that drive is formatted.
Please also provide a dxdiag. Click Windows key-R, enter dxdiag in the run box, wait for the scan to finish, click "Save all information," and save the file to your desktop. From there, you can attach it to a reply using the paper clip (Attachment) icon included with the other formatting buttons.