What causes a computer to freeze up while viewing a DVD or streaming a video clip or trailer?

First check you're not running too many programs; if so close some down.

It could be your graphics card is outdated; try upgrading the drivers.

Another possibility is that the file you're trying to play is not supported. This could either be because it is a bad download (if the video has been downloaded) or because your computer does not have the right codec installed to play the file.

If you're running Google Chrome, and you're streaming from a site that relies heavily on Flash, you may encounter Shockwave Flash errors that cause performance issues. There are work around's for this type of issue - Just do a search for "stop shockwave flash error chrome".

Lastly, if it's a DVD, ensure there are no scratches on the disc.

Another causes to this problem can be that your power supply does not give enough power to your GPU (graphical processing unit).