Cannot locate my mail server or Web sites

It's not clear from your scenario whether you can resolve names from the console of the server running NAT. Assuming...

that this works, then where do you have the client pointed for DNS?

Since you have DNS turned off at the Win2k server, you will need to point the client at your ISP's name server. You could also turn on DNS at the server then configure it to use the ISP's name server as a forwarder. Then point the client at the Win2k server for name resolution. You will need to delete the root zone on the Win2k DNS server before you can enable forwarding.

If the client still cannot resolve a name, try flushing the DNS resolver cache using "ipconfig /flushdns."

If the client still cannot resolve a name, make sure you do not have firewall software or some other kind of blocking program running on the Win2k server. Also, make sure you have not enabled packet filtering.