Quit the program, then go to the 'uninstall a program' menu in Windows, and uninstall it.
Thanks Samperson, I DID uninstall it in the standard Windows 10 programs uninstall process. It's gone from my list of installed programs. And it's not running now, but it STILL SHOWS UP as a program in my "Startup" programs folder. I can turn it on or off in there even though I uninstalled it via Windows.