Hi Virginia - I'm having the same issue - Bluetooth was previously working, then disappeared from Device Manager. I tried all the steps you suggested, and others on this thread, none of them worked. Bluetooth Troubleshooter says 'Device doesn't have bluetooth.' Any other suggestions?
Ok, none of this changing Windows-settings worked for me. My solution was buying a $12 External Bluetooth Adapter. Plugged it in - and that fixed the problem!