madapeach Please try playing in a clean user folder. Move the entire Sims 4 folder out of Documents > Electronic Arts and onto your desktop. When you launch the game, a clean folder will spawn with no content. (Your saves and other content will be intact in the folder you've moved but temporarily unread by the game.) Don't add anything to the new folder yet; just start a new save and see whether you can play in live mode. You don't need to spend much time on the sims; this is just a test.
If you can't play in live mode, please 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.
If the new save does work, please copy your main save from the old Sims 4 folder to the new one. Saves are in the saves folder, of course, and you can sort them by modified date to find the newest one.
If your main save doesn't work, you can try recovering a backup:
https://sims4.crinrict.com/eng/2014/09/recover-backup-save-game/
Let me know how it goes, and we can figure out what to do from there.