Computer speakers help

[Evil ... Thy name is Orville Redenbacher!!]

I have a DVD I want to play on a laptop computer through speakers. It's a old mm movie footage narrated by a historian. The audio will only play through one of the speakers.
Any idea why this is happening and if it can be fixed? I need to improve (better volume and quality) the sound of the DVD.
The issue is not the speakers.

Help?

 

[spikechiquet]

May not be recorded in stereo. Use a mono plug in with a stereo plug out and both speakers should work for you.