What's the extension of the video (mpeg, avi, wmv etc)?

What player(s) are you using?

Have you had the same problem with other videos?

Do you see any error messages when you try to play the video?

Did you check the file with Bitzi before download?
How to use Bitzi

Try playing the file with VLC player. VLC's a free download & has codecs installed to play most file types: VLC - (click on link)