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.
If this was caused by Windows Updates 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 then run a Repair Install by installing the Media Creation Tool and choosing from it to Upgrade Now. This solves many problems and will also bring 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...
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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