Hi Hugues. I'm Greg, an installation specialist and 9 year Windows MVP, here to help you.
TROUBLESHOOT BLUETOOTH:
See Fixes here:
https://support.microsoft.com/en-us/help/14169/...
http://superuser.com/questions/823894/how-to-ma...
Try the Bluetooth troubleshooter at Settings > Update & Security > Troubleshoot.
Try turning off Fast Startup at Settings > System > Power & Sleep > Additional Power Settings > Choose what Power buttons do > Change settings that are unavailable > uncheck Fast Startup.
Try Updating the Bluetooth driver from the PC maker's Support Downloads webpage for your exact model. Install it even if it's the same or newer than the one in Device Manager reached by right clicking the Start button.
Right click Start button to access Device Manager, locate Bluetooth device (if necessary from View tab Show Hidden Devices), on Driver tab see if Roll Back is available, if not try Update Driver, first automatically, then Browse, then Let Me Pick to try all previously installed Drivers.
If these fail try to Uninstall the Driver, restart PC to reinstall.
Then try pairing again, if necessary run the Bluetooth Troubleshooter again.
Troubleshoot Right click Volume icon in System Tray at right end of task bar, Open Sound Settings, in dropdown menu at top make sure Headphones are selected.
If not choose Troubleshoot.
Also try the Hardware Troubleshooter at Settings > Update & Security >
TROUBLESHOOT HEADSET:
Go to the Device Manager reached by right clicking the Start button, choose Sound controller device, on Driver tab choose Roll back or Uninstall, restart PC using keyboard to Ctrl Alt Del, on blue screen tab to Power Icon in bottom right, press Enter, arrow down to Restart, press Enter to restart to reinstall the driver.
Update the Sound driver from the PC or Device maker's Support downloads web page. While there also check that the Chipset, BIOS, Display, USB, Network and all other drivers are the most current.
If this was caused by Windows Update(s) then you can check which were installed at Settings>Update & Security>Windows Update under Installed Updates, then uninstall them from the link there, and hide with the Hide Updates tool downloaded from here: http://download.microsoft.com/download/f/2/2/f2...
You can also use System Restore to get before the problem began, then check for Updates with the Hide Update tool and hide them: http://home.bt.com/tech-gadgets/computing/how-t...
Go over this checklist to make sure the install is set up correctly, optimized for best performance, and any needed repairs get done: http://answers.microsoft.com/en-us/windows/wiki...
Start with Step 4 to turn off Startup freeloaders which can conflict and cause issues, then Step 7 to check for infection the most thorough way, then step 10 to check for damaged System Files. Then continue with the other steps to go over your install most thoroughly.
If nothing else helps you can run a Repair Install by installing the Media Creation Tool and choosing from it to Upgrade Now. This reinstalls Windows in about an hour while saving your files, apps and most settings, solves many problems while also bringing it up to the latest version which you need anyway and by the most stable method. http://windows.microsoft.com/en-us/windows-10/m...
But remember that in Windows 10 everything depends upon the quality of the install, and Factory or Upgrade installs are inferior installs which most enthusiasts won't even run because they'd expect endless issues. Consider now or later doing the Clean Install in this link which compiles the best possible install that will stay that way as long as you stick with the tools and methods given: http://answers.microsoft.com/en-us/windows/wiki...
There is also an automated Fresh Start that reinstalls WIndows while shedding corrupting factory bloatware, saves your files, but doesn't clear the drive to get it cleanest: https://www.howtogeek.com/265054/how-to-easily-...
I hope this helps. Feel free to ask back any questions and let us know how it goes. I will keep working with you until it's resolved.
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