I am not at all sure what happened, but I have been checking the status of my virus protection about everyday.
Windows Defender is off and Bitdefender is working and active.
I believe it was...

I upgraded to windows 10 from 8.1 yesterday
I have windows 10 home,x64. I also have bitdefender free version and it appears to be "on". Windows Defender says that it is on also. On the internet,...