It happened to me and when the pop up came up I immediately hit alt-f4 and closed the box, i remember this working but it could have been a different pop up than the one you are referring to.
All the ones I mentioned in my post above are free, Spybot and Hitman Pro (free 1 month trial) have found things on my PC that Aviva and Malwarebytes didn't
If you beleive this is true. Then 1, you're not an IT guy and 2, don't claim to know anything about computers other than the fact that you know how to surf the net.