Server 2003 Installation Help

Hello all, your help would be appreciated with the following problem. I am a novice with Windows Server 2003 and in an effort to learn more I have installed Server 2003 on an old PC (The PC complies with the min specs for 2003).
The basic installation went fine until I attempted to add Active Directory when I received the following message;

Active Directory installation operation failed; a general network error occurred.

Despite rerunning the AD installation wizard I cannot install AD. As a side issue I also cannot connect to the internet after attempting to install AD.

My first instinct was that there was a connection problem with either my ISP, router or network card. After checking the ISP/Router I attempted to reinstall the network card at wich point the internet connection returned.

I then attempted to reinstall AD and got the same result;

Active Directory installation operation failed; a general network error occurred.

I've now replaced the NIC but with the same result!

I've also checked the event log and found the following error at a corresponding time to each attempted AD install;

Error Event ID 7003
The Distributed File System service depends on the following nonexistent service: LanmanWorkstation.

This error seems to refer to the Client for Microsoft Networks but how it is relevant I don't know.

Any thoughts anybody?