A family of Microsoft word processing software products for creating web, email, and print documents.
Sorry to hear that you're having trouble with this. Could you please provide a little more information? What version of macOS are you currently using? In Word, please go to Word > About Microsoft Word and me know the exact version number.
When you say you cannot open files, what exactly happens? Do you receive an error message, are the files grayed out, or does nothing happen? If there is an error, please share a screenshot. Does this happen with every Word document, including a newly created document, or only with certain files?