Just an update for those looking for a follow-up:

No success yet, haven't resorted to a hard drive reformat (I went away
on vacation for a couple weeks, and knew it shoouldn't be attempted
until my return).

SpyBot S&D & Norton continue to find nothing, AdAware just found an
Alexa thang in my registry.

Whatever it was, was idle a couple of days ago (making me think it
went away all by itself...) but returned yesterday.

Frank Lynch
The Samuel Johnson Sound Bite Page is at:
http://www.samueljohnson.com/