[NAME]  Which BT do you have, Qualcomm or Killer or Intel, and is it listed in Device Manager? If BT not  listed, is WiFi card listed and still working? (They're both on same physical card.) Not sure I understand... " hitting the power button for 10 seconds then removing the device and rebooting after scanning for new hardware." How do you remove the device after "hitting power button..."? Did you do a reboot in between? And did you unplug the power cord from PC, rather than just from the wall? You should uninstall the "Unknown" device(s) before you power off, etc. And be sure to set Device Manager to "Show hidden devices", and uninstall any "Unknown" that shows up there too.
Yesterday everything worked in my new Dell XPS8930.  Today Bluetooth is showing as not available.  I'm showing an unknown USB Device in device manager.  I've tried turning off the computer, unplugging and hitting the power button for 10 seconds then removing the device and rebooting after scanning for new hardware.  The bug comes back.  I've tried updating drivers but those also appear to be up to date.  How can I reset and reenable Bluetooth?
XPS 8930, Bluetooth stopped working