A video file or a movie will not play, or you only have sound, or only...

For 90% of video playback problems..

Just download FFDShow and vlc MEDIA PLAYER.
Its extremely rare with this combination, to find a movie file that wouldn't play, and if it doesn't play with these two, its probably a fake one.

get FFDShow here, its the first link http://www.free-codecs.com/FFDShow_download.htm

with ffdshow all you need to do is to run the setup file and click next repeatedly untill the setup is complete, and then just finish it, close it and its done, works on the background when movies are played,

more info about FFDShow - http://www.free-codecs.com/download/FFDShow.htm

vlc media player - http://www.videolan.org/vlc/

After you got these two installed, you should be able to play most if not all of the movies out there.

Note that there are some file formats that will not work with these two, I think mov and Realmedia player files will not play with these two, there are also many other file formats that are rare and may not work with these two another player or codec may be required. for mov files Quicktime is required etc.

Thanks,
E