Thanks for all the responses, guys. I'll address each in the order of their posts.

Jim, thanks for the link to that utility. This is something I was hoping was internal to Windows, but apparently it isn't. So I'm running it right now, and it's providing me with a ton of information that I've just started trying to sift through. Cursory examination reveals, however, that the USB ports I was using are behaving normally. They are "active" in this utility. I'll have to play around more with this, see what if anything I can do with it to possibly solve my problem.

Andrew, as I mentioned above, I have not yet tried plugging the amp into a rear port. This has to do mostly with reaching one of them without disturbing a festoon of wiring back there. I really am not looking forward to having to pull out the CPU and disturb all that stuff, just so I can plug in a USB cable. As for the reliability of the front ports, I've had no problems with them. None. Except for this amp. So I don't consider them to be unreliable.

Bob, I've already tried other USB ports. Didn't make any difference.

VideoTrack, this is not a laptop.

Guitarhacker, if I choose to go audio, the amp has a line out. So no need to mess with a microphone. And if I can't solve this issue, that's exactly what I intend to do.

Best,
Michael

My Music:
https://soundcloud.com/michaelmcbroom/albums