What are some ways to enhance the security of a work PC?

Hi everyone! I work as a receptionist at a cosmetic surgery clinic. As a result, we have a lot of sensitive information about our patients that we store on a single computer at our clinic. Although we regularly update and upgrade our systems to ensure that the private data of the patients stays private, we are always open to suggestions to enhance our security measures. I want to make certain that no data is ever compromised. I am looking for suggestions that could help and further enhance our security systems. I would truly be grateful for all of your input. Thank you!