This folder contains open source - free - video player software called VLC for Mac and for PC. It is available here, but I have saved it to disk for you. The file is quite small and it is quick and easy to install and run.
I have found very few video formats that the VLC player is not able to run, as well as any other media player. I have found Windows media player to be quite limited, but Real player (also a free version available online) to be very good.