Client pc’s need to be members of the new domain.
In the clients, go to <control panel> and double click the <system> icon. Select the “Computer name” tab, click on the “Change” button, under de “Member of” frame, select “Domain” and write the domain name in the corresponding text box, then click on “Ok”. You will be asked for user account; use any domain user account (administrator or not).
Hope this helps.