Hi, everyone. Many thanks for the replies. If I weren't so spec-clueless (is that a word?), I would have given all that data gladly. As it stands, my set-up isn't much of one--no audio interface, apparently no sound card (which *does* explain why I can't locate it in my system!), and my sound source a Casio WK-3800 synth, which I'm using for audio, MIDI input, and multi-channel MIDI playback (though the Casio's "Mixer" is quirky, to put it mildly). My best results, to date, have been with recording Casio parts/tones and mixing them--as opposed to so-so results using MIDI in and out. I suspect Casio's sound mixing is inadequate. (Is that the definition of a given?)
Hopefully, I haven't broken a forum rule by mentioning Casio! (-: The WK-3800 has some great patches/tones, as in, far better than the brand name suggests. However, given its terrible tone mixing/layering, I wonder if MIDI playback will be a problem even if/when I buy an audio interface (essentially an external sound card?).
At first chance, I'll reference the unhelpful Help page.