Did you install the codec pack?:
http://www.cccp-project.net/download.php?type=cccp
If that doesn't work you will probably have to use VLC player. Should be easy to find on google. Sometimes there is something installed that prevents the player from using the correct codec. VLC player has the codecs built in I think. I've tried VLC player before I didn't like it because it associates all audio and video files to it. You can always uninstall it later though.
If you are using windows media player, you should be able to right click on the video and select properties and it should tell you which codec it is using. It should say ffdshow video decoder or H264.
I'll go ask the pit workers what time the gates will be open for competitors. I'm guessing 7:30, but I'll go check to make sure.
-Toby