Thanks again for all the input, and I'd not intended to ask anymore dumb questions, but I happened to call a pal in Ireland just as his guru was working on his kit. I mentioned my problem and he said words to the effect that there may be a multiplicity of unwanted drivers lurking. He was obviously a big systems man and so far, hadn't had much to do with W7, but he suggested turning on "Show Hidden Devices" in device manager.
It didn't reveal any new files, but I'm not skilled enough to know if I'm not jumping to conclusions as to where they should be.
Any thoughts on this line of logic?
It is defeatist, but I'm ready now to A/ Get a sound card. B/Get some kit that will interface with the 'Realtek Digital Output'. (HMDI) or C/ Do a 250lb version of Riverdance on it.