|Sounds to me like you don't have DNS properly configured. Look at your workstation dns entries. Are they pointing to your Microsoft DNS server or to the ISP's DNS servers?|
It should be pointing to your Microsoft DNS server as should all the other workstations.
It works like this: your isp dns server can not be updated by your clients. if you point to the isp's dns you can never resolve local host names because it doesn't know about them. This is why you point to your local MS DNS which CAN be updated by your clients. It in turn, since you put the isps dns servers in the Forwarders Tab, would refer a request for say Google to the isps dns since it could not resolve it locally.
Give a person a fish, they eat for a day. Suggest they internet search and they learn a skill for a lifetime.