Some other research I've done says that Toshiba has an internal hardware problem regarding sound, and that the laptop's sound doesn't work after awhile (I've had mine for about 3 yr) but that if you plug in externals, those will work sometimes. Dang Toshiba. Last time I'll buy one.
So it is possible that you are experiencing the Toshiba hardware issue as well. If I find out anything else, I'll let you know.