Old domain 2000 server had the DNS, DHCP and Active directory on it. Co. had no BDC. Set new 2003 R2 small office DC server up as directed as a new DC (with the same domain name as they had) and ran and activated the DNS, DHCP, and active directory. The problem: Created a few users in active directory with the same user loggin as the old server, took the test Pc and put back into workgroup and tried to add to new domain server with same domain name. Will not take. Tried to ping new server from that PC and different PC's cannot ping new DC server but PC's can ping other PC's and router. New DC can ping PC's and router. So therefore i can't add Xp PC to Domain because they cannot see new DC server. It has 2 NIC cards. Disabled one. Do get a defualt gateway warning for redundency? PLEASE HELP>>> The new PDC server can ping PC's and router...what am I doing wrong?

Usually you upgrade your existing AD with adprep and then add the new DC to the exising forest. This way you keep all of your users/ad settings. You created a new forest and new domain instead. You can't have two dhcp servers. That is a problem. Odds are you don't have the test pc pointing to the new server for dns or if it is server dns isn't configured correctly.

"Tried to ping new server from that PC and different PC's cannot ping new DC server but PC's can ping other PC's and router" Why are you doing that? 2003 is locked down by default. If it pings one way you don't need to ping the other way! "New DC can ping PC's" SEE you KNOW it connects. Review how to add a computer to an AD domain. "Best Practices", Event viewer, host file, perfmon, antivirus, anti-spyware, Live CD's, backups, are in my top 10