The devices do not show on Device Manager. My two USB external hard drives live in docking stations on my desk. They show up under "Portable Devices", and are functioning normally.

Another computer... I have my wife's iMac, would that show anything useful? I know that five different Kindles didn't all suddenly die four days ago and take all the cell phones in the house with them.

Oh, wait, there is an old laptop, been sitting on the shelf for the last five years or so, I'll see if I can round up a charger for it and try that.

From what you're saying, it seems likely that the MTP part of the USB system is the problem. In that case, what do I do about it? Is it hardware or software? Do I have to reinstall Windows, or is there a repair utility? I have pretty good backups on hand...

tanstaafl.