McAfee fixed the problem easily today when they restored the firewall settings on my computer to default with one click and Gmail can now be accessed with no problem. Thanks McAfee.
Glad that you are Ok now and thanks for taking your time to provide us with a status of your issue , Much appreciated !!!
Thank you, Dinz, for your interest. You may be interested to know that the problem recurs after a shutdown/restart and I have to reset the firewall to default each time. Do you know of a more permanent solution? Could this have anything to do with the Gmail default setting of HTTPS? This can be changed, if needed.