Thought I would update this post since the problem has been resolved. Perhaps someone may find the solution helpful.
Checking the overall control page of system Mechanic, I found that supposedly McAfee Virus Scan was operating on my computer (I had never knowingly installed any McAfee program.). Using Search could not locate the McAfee files and neither could three separate uninstaller programs. I emailed System Mechanic about the problem and they suggested going to McAfee.
I did that this morning and found that McAfee offers a couple of levels of free tech help. One, a virtual technician, scanned my computer and said there was no McAfee product installed. Next, I went to the free tech chat. Filling out a brief questionnaire before the chat began enabled the support tech to already know the problem with his "Good morning" greeting. Eventually, after perhaps five minutes of courteous and pertinent exchange between us, he sent me a url to get a super uninstaller of all McAfee products, from full applications to remnants, from my computer. I ran that and it found numerous bits and pieces. A restart after it finished and I checked again to see if System Mechanic still indicated that McAfee Virus Scan, or any other AV program, was still running. It showed that there wasn't.
So, it appears that everything is clear again.