sound question

[Linda Hanigan]

I have never used sound on my computer, but I downloaded a wmv file and
tried to play it with mplayer, the default player wouldn't work some
sort of error totem can't play may need plugin. Anyway the movie plays
with mplayer, but has no sound. Any ideas where I start looking to fix
it. The sound should be an onboard sound not a seperate card. I am using
Ubuntu 6.06
                              Thanks
                               Linda