Thank you Maxx_original.

I refer you to the thread at http://forum.avast.com/index.php?topic=88741.0

I observe the considerable beneficial effects in performance at startup. The system is now ready for use after a much shorter time, i.e. the wait is now tolerable. The self-defense module seems to prevent attempts to subvert the Avast! files. I have confidence in the self-defense module. Is that confidence well founded?