Thanks very much for replying, drragostea.
<<< have you removed v.1.4 before installing the latest version? >>>
Actually, no ... I'd read in some other threads that v1.5.2 could overwrite the existing v1.4, so I did not delete 1.4 first.
I appreciate the link you provided. While I thought I had a good understanding of how SpyBot worked, the thread you linked gave an excellent detailed description which I've PDFed for safekeeping.
So, I guess my question now is, should I go back and delete all of SpyBot completely and start over again? Or should I just pick up at the point where you advise to deactivate Webroot's Spy Sweeper and try to immunize with the current install of SpyBot?