I didn't find anything related to Google Search engine restore on any of the visited websites (including Samsung Support), therefore it's best to reset the device to factory settings. Since it's a Smart TV, the process shouldn't take longer than a few minutes tops.
Additionally, follow the guide on the Samsung support page where you can find all the steps to reset the TV.
Samsung Support: http://www.samsung.com/ie/support/skp/faq/1057786
