Cannot connect to other machines in Domain

Ok weird issue. Client has an SBS 2008 server with about 8 workstations on the domain. I cannot connect to get them to connect to each other. I try to ping another workstation with all packets failed "Request timed out" I can ping the server from a workstation but not the server to workstation. I can see all the workstations when you look at the network. Cannot view a shared drive, cannot RDP cannot Ping. I have disabled firewall (win 7) and win defender and AV. Nothing. I have remote access to them from labtech I can RDP to the server from the workstations. I did not setup the environment. They are running a Cisco/Linksys switch (do not model yet) and a D-Link residential router. Server is a Domain controller both DHCP and DNS. I don't see any group policy that would stop this.