I just figured out a frustrating computer configuration issue so I thought I'd share the solution.
I recently bought a set of Bluetooth headphones but was unable to get them to work with either of my computers. The headphones worked fine with my mobile phone, and would successfully "pair" with the computers. However, once they were paired the computers would not recognize the headphones as an audio device. The computers had the generic Bluetooth adapter drivers from Microsoft, so I assumed that the problem was with the headphones.
But nope, the problem was with the Bluetooth drivers! The generic driver will let your computer pair with any Bluetooth device, but it doesn't know how to use most things, including audio devices. Consequently, even though the headphones showed as paired the Device Manager control panel showed them as unknown devices and the Sound control panel didn't show them at all.
The solution was simple enough: download and install the manufacturer's drivers for the Bluetooth adapter.
I was so used to the generic drivers working for everything -- or Windows Update magically finding the right drivers -- that I just didn't think in this direction early in the troubleshooting process.