Int 1A Fn FF05  - Snd - Unconditionally Stop Sound                         [s]

   AX = FF05h

Return: AH = 00h (successful)

Note:  this function is the same as AX=FF03h, but will stop the sound even if
     SND is currently busy, such as playing background music

See Also: AX=FF00h,AX=FF03h,INT 80/BX=0007h