I left the computer running when I went out to do some other stuff in the house,  and sort of forgot that, when I came back down the hall and thought "I wonder if the big fireworks shows in the East are on TV yet." 

While I was gone, AVG did its automatic update of definitions, etc.   Later, I went back in and found myself staring at the message no one wants to see (though it wasn't phrased this way): "You've got Virus!"    

All's well that ends well, and though I'm still running checks and am ab