pandzia68 Inside the "The Sims 25" folder is one subfolder per neighborhood, labeled UserDataX, with the X corresponding to the neighborhood's number (except for 1, which has no number). So if you remember which neighborhood your household was in, restore only that UserData folder. However, keep the newer UserData folder in case you need it. Just drag it out of the folder to your desktop.
If that doesn't help, remove the old UserData folder and copy (don't move) the newer one, that doesn't contain your sims, back to the Sims 25 folder. Start replacing its contents with copies of the contents from the folder that contains your old household, the idea being to add whichever files or folders are required to restore your sims without making the game crash again. Let me know what you find, or feel free to ask for more detailed help.