Happy New Year Gary and thanks for your reply.

I had Comcast replace the modem and we can go now for a full week without problems but then we will get a day when Ping Plotter shows lots of packet loss and we lose internet connectivity until the modem is reset.
The odd thing is and hopefully you can shed some light on this, when Ping Plotter was showing 100% packet loss and we had no Internet, my LAN was fine and I, as well as the Comcast tech was able to access the modem GUI and use it's diagnostic tool to ping the same 8.8.8.8 at the very time that Ping Plotter was showing 100% packet loss and no Internet was accessible.
Power cycling the modem fixed it all.
The PC that I was testing from is wired directly to a port on the modem, bypassing am switches.
I had another test running on a PC connected through the switches and same result.
Has me baffled.
Thanks.