Thanks for your suggestions.
Unfortunately, I've checked and done every one of them with no results, and I just did them all again to make sure
To recap, I'm using 32-bit Windows Vista on a fairly new Sony VAIO laptop
UAC is disabled
Wav fles and MIDI files play under other software, just not in BB
Under BB options (BB 2008.5), I hit "return to all factory settings, including MIDI"
MIDI settings are: NO MIDI INPUT, Microsoft GS Wavetable Synth and VSC DXI checked (same as always - I also tried running it with DXI not checked, and it makes no difference)
In VSC DXI panel, master volume is all the way up, all sliders all the way up, all boxes set to receive, and I've hit reset to make sure
Windows Volume control shows BB volume all the way up
Sound card settings all good
No audio file in BB - I'm opening up files with no audio, opening new files, etc - no audio showing in audio edit window
Q: I lost the sound after plugging a microphone into the microphone port of the laptop to record an audio file - it was the first time I had ever done that in BB (usually record in RealBand - BTW, sound is still fine in RealBand) - can you think of a way recording an audio file in BB could have disabled the sound? That's when it happened, anyway. Could it have something to do with the registry?