>If yours does NOT beep at power-on then I would guess that some tampering with the beep speaker has been done. If it does beep on power-on, then I have no idea why something like "?? chr(7)" doesn't work from the command window (it does here on my speakered machines).

If your machine has a sound card then ??CHR(7) comes out of the sound card, not the internal PC speaker. I don't think you can still use the internal speaker (after the POST) when you have a working sound card installed.