Hi,
Keep your internal DNS on your server and remove the "." corresponding to the roots servers. This will allow you to add forwarders to your ISP's DNS? This might require to reboot. But i'm absolutely sure it works.
The test order is:
--> ping your ISP's DNS server with its IP from your server
--> ping a web site IP from your server
--> ping a web site name from your server
Your server is properly configured
--> ping your server IP from your client
--> ping your ISP's DNS server with it's IP from your client
--> ping a web site name from your client
Also verify client IP configuration, such as Gateway and DNS server...
PS: ICS is best used with W2k Pro, W2K Server integrates RRAS service which is designed for your needs... you can find informations to configure RRAS on www.microsoft.com/technet
Bye