Why is my S5 now an "Unspecified Device" & won't connect properly? (PC)

A

AC Question

I know that this has been brought up before, but after trying every e-solution I can find, and with no search hits in recent months with new information, I'm forced to make a new thread.

My S5 is not connecting properly. Here's the list so far:

* It has connected to this PC successfully in the past.
* The phone is unlocked when attempting.
* I'm using the device's original, Samsung usb3 cable. The cable works: The device connects to a tablet just fine.
* I have tried from multiple USB ports.
* I have rebooted the device, and the PC, more than once.
* I have removed the battery and rebooted the device.
* Power-saving is disabled.
* Yes, I've set it to MTP. I've also tried MTP + ADB. Neither mode works.
* I installed Smart Switch. It fails to connect to the device. None of that program's suggestions remedy the problem.
* I've reinstalled the drivers and checked for updates, more than once.

Before tonight, I hadn't connected the phone to my PC in at least a couple of months. Since then the only changes I can think of are OS updates. The latest for my phone, and Windows 10 for my PC.

Other notes: Windows does make its connected sound, and under "Devices & Printers", the phone is sitting there under the "Unspecified" category, mocking me.

Since it does connect to my tablet, I'm assuming that there is a PC issue somewhere, maybe a Windows 10 issue. Again, the drivers are fully updated (multiple times), and power saving is disabled.

Does anyone have any other ideas?

Thank you.