Can anyone tell me soon if I can put all my old files back having run the updater? Will the site still work. Or do I need to replace the database as well? Please advise as I'm losing sales as we speak. Thanks.
You can't just put back the old files as they will be on a different version from the database. You would need to get a previous back up from your host or one that you made (if available). Much better to try my suggestion in your other thread and stick to that one.