How to Recover AD & DC

My office had a Windows Server 2003 Server. It has two role installed, AD & DC. I’ve successfully migrate the server to a new hardware server on Windows Server 2008 R2. When I change the host name of the new server with the following command it failed to load the AD & DNS –

netdom computername /add:

netdom computername /makeprimary:

It changed the host name but it failed load the AD & DNS.

Now can anyone help me how to recover the AD & DNS from this situation.

Pls…pls…pls…