Thanks for responding. Unfortunately, the plot is thickening.
Clicking on your link, I tried the first 2 suggestions, which didn't work. The 3rd one referred me to another security-related link that said I needed to have the latest version of itunes. So I downloaded it, but it would not install. Here are the messages I got:
"The feature you are trying to use is on a network resource that is unavailable. Click OK to try again, or enter an alternate path to a folder containing the installation package 'iTunes64.msi' in the box below."
The box below is a browser window, but I was unable to browse to this installation package. Neither could the seach engine in the Start button find it. So, when I clicked OK, I got this message:
"The path 'C:\Users\David\AppData\Local\Temp\IXP033.TMP\iTunes64.msi' cannot be found. Verify that you have access to this location and try again, or try to find the installation package 'iTunes64.msi' in a folder from which you can install the product iTunes."
But that installation package is not on my computer (nor is IXP033.TMP). So, then, when I try to click off that window, I get THIS message:
"The older version of iTunes cannot be removed. Contact your technical support group."