More to add
First, firewall is disabled.
Doing some poking around on the Westell DSL modem/router I found that two computers have a status of Inactive. I cannot ping anyone internal from those computers. But one can reach the internet. The new one cannot reach the internet. The active computer, mine, can ping my servers and the printers, but not the other two computers. Westell provide DHCP. Westell will show the IP, MAC, host name, and status. Since Westell can get the MAC and HOST name, I know it is talking to the computers. But why can't the computers talk?
Called CenturyTel (ISP) and they were worthless. The tech was actually googling to get me some information. They were not aware that their modem provided routing and NAT.
A positive attitude may not solve all your problems, but it will annoy enough people to make it worth the effort. (Herm Albright)