Solved
Just before I left, I realized that another computer on my network was also unable to access the internet or email. The one that I'm currently posting with was totally unaffected.
This revelation gave me something to think about on the way to the job. Since they all are connected to the same switch and go through the same smoothwall firewall either the firewall settings had been altered or a problem with the switch had occurred.
When I returned, I immediately switched cables between the working system and a non working system on the switch to no effect. So the switch was not the problem. I checked their ip addresses and started looking around in the firewall to try to find if any settings had been changed. None were obvious but I did notice that the one ip that had internet access is one that I had added to a list that in essence forces a connection. I added the other 2 ip addresses and the internet immediately came up on both of the other systems.
After thinking about it, at the time yesterday that I first disabled the Web Shield (when the problem first started) I was logged into and had the smoothwall firewall configuration window open on the same system that I was currently configuring Avast on.
Is it possible that Avast somehow interacted with smoothwall? I haven't found any obvious changes made within smoothwall other than what I just did to correct the access problem. The only change yesterday was to open the necessary port for steam.
Thanks again for your assistance and let me know what you think about what occurred
Monty