The most basic security step is to make sure your computer software is up to date. Microsoft releases regular updates — you may hear them called "patches" in the news media — to combat new threats as they appear. These updates are available for Microsoft Windows and Microsoft Office.
A wise computer user checks for updates regularly and installs them. All the updates for both Windows and Office are found on the Microsoft Update site.
You can even set up Microsoft Update to automatically download and install new updates as they become available. So once you've set it up, it will run all by itself.