On some toshiba laptops, there is a switch near the edge of the computer to turn on or off the wireless, and the sound.
It may be installed perfectly fine on the computer, and you may have the volume cranked all the way up, but if that switch is off, no sound will come out of the speakers.
Again, check around the computer, and if necessary, find the manual for the laptop and look to see if they have an audio switch on it.
Hope this helps!