I don't have much experience with Win8, but what I gathered is that it is windows 7, slightly dumbed down, with the Windows RT interface tacked on top of it. Windows RT is the ARM processor-based OS for tablets that won't run most Windows programs. They are apparently going for a unified "experience" on any device, including Windows phone devices. Ugh.
Anyway, internally Windows 8 doesn't add much above 7, and in reality it is actually Windows NT 6.2, where Windows 7 is only version 6.1. Vista would be 6.0, though all the 6.x versions are, at the core, still Windows NT 5.0. All the 6.x stuff is just eye candy (aka bloat). And the primary goal of 8/RT/phone is to promote the touch screen stuff, which I think will go out of style on the PC platform. It's great for phones and tablets, but I don't believe it will survive the PC platform.
For one, a touch monitor (which I've been pricing) for a PC/laptop is VERY expensive. Also, the PC needs more intelligent interactions, like, oh, I don't know, a real physical keyboard and perhaps a pointing device. In other words, it's a fad, trying to take the tablet interface to the desktop...
Enough ranting about Microsoft (I do that a lot). The bottom line is, there simply MUST be some common thread on this buzzing problem. After a few years, one would think a root problem would have been discovered, which is why this intrigues me. I'd love to know the common thread - CPU/heat problems, virus, bad driver, or something else...
I just looked at the links you provided, and I kinda noticed a trend in the usernames of the official support techs, who keep parroting the same answers... but I'll digress before I get into that issue...
One question though - have you ever installed any third-party audio driver (specifically ASIO) promising lower latency etc? I know from experience that some ASIO drivers not only mess up the sound system, but they also don't uninstall easily. You remove the driver, but then you plug in another USB sound card and Windows uses that third-party driver all over again...