Hi Michael,
All Windows machines have IE installed by default. If your default browser is not IE you can always open IE and copy the link from room viewer into the address bar of IE.
You also need to know that Room Viewer will only work with IE 10 or IE 11 running in compatibility mode.
Room Viewer has largely been replaced by the 360 panoramic view at this point and since it will work in any browser I would suggest moving to that solution.
Hope that helps
Neil