>Now here is something interesting.
>
>SET BELL OFF
>? CHR(7)
>
>
>and the bell still rings.
Set Bell Off just tells Fox to not ring a bell on error, i.e. not to raise the event - not to call the system service which then plays the sound. Now if you ? CHR(7) you are yanking that bell manually. Fox has no way of removing a system service... and chr(7) taps somewhere into the DOS bowels of the system's console interface, who knows how deep inside or deep in the past... I don't think there's a way to stop that.
Did you try to press ctrl+S while your machine boots and the BIOS is still churning strings to screen in character mode? That's another one like that, aged roughly the same. Ctrl+s is the equivalent of Set Console ON/OFF.