I finally got a Tech Support rep who, after suggesting some things himself, passed me on to a tier2 tech. He connected with my computer and, after well over an hour of uninstalling and reinstalling various programs and making setting changes, seemed to have the problem solved. I should have checked things myself before we ended our chat. Unfortunately, the original problem remains, i.e., although I can get the Site Advisor rating icons by using the
www.l.google.com workaround, or the Google search box on the Firefox navigation toolbar, or by using the McAfee search box that now appears to the left of the green Site Advisor icon in the lower right corner of the window,
I still can't get the rating icons when I simply do a search at www.google.com. At this point, I don't know how to get back in touch with that tier2 tech, and don't have the heart to do so. I'm waving the white flag of surrender and will use a workaround. However, I'll check back to this thread for a few days to see if anyone else had better success than I.