Reader Richard Shew sends in this short but sweet Tech Support story: 

I'm the IT Director for a manufacturing company in the midwest.  I had one of our Sales guys ask me the other day why his anti-virus software did not seem to be scanning his computer at night like he had set it up.  I asked him if he had created a "scheduled scan" with a time and recurring day.  He told me he had done that.  Suspecting something was amiss, I said, "You know, the computer needs to be on for the nightly scan to work."  He looked at me and said, "Oh, that's probably the problem, I always turn the computer off at night."