Why can't I watch videos on the internet on my laptop?

[PJ]

Is this a downloaded video file or a file you are trying to stream from an internet site?
Can you watch videos on other websites? the box with the x more than likely means that the computer doesn't have the right program or plug-in installed to run that type of video file.

If the file is a downloaded video file, I would suggest downloading and installing vlc media player (http://www.videolan.org/vlc/index.html) to see if the file can play in that... it will play most video and audio files that windows media player (which is the default player for any Windows computer) might not be able to play.