open media player.
go to tools and options.
control tab until you land on the devices tab.
next tab once to a list, where it shows your DVD drive, display and speakers.
arrow down to speakers.
tab twice to the properties button.
hit the space bar.
arrow to the sound card of choice.
hit alt + the letter A to apply the change you just made.
hit enter.
tab to the OK button.
hit enter again.
unload then restart media player so your changes can take affect.