Norton Security Scan appears on my computer and I cannot uninstall it

Today, 4 July 2015, I noticed a lot of hard drive action and opened Task Manager (in Windows 8.1) to learn what was going on.  I then saw that Norton Security Scan was busy at work even though I didn't install it.

I tried removing it under Programs \ Features in Control Panel but the removal process stayed at 0 percent for at least 30 minutes.   I downloaded the Norton Removal Tool (after restarting my computer), ran it, but the program is still on my computer.

How can I remove this ... and is NSS part of the update from Windows 8.1 to Windows 10?

Thanks, Dave Horne ...