Our company has two locations and each location has a Windows Server 2003 machine as the DC and several servers, running on two different sub-nets. We are consolidating the locations. I changed the IP address on one of the web servers prior to moving to the main location. I didn't change the IP address on either the DC or the other web servers prior to moving to the main location. Now, only the web server whose IP was changed is able to serve pages. The other web servers are not able to serve pages, cannot be pinged, or be accessed via RDP. Since we don't need the second DC, it has been powered down. When I tried to ping it, the previous IP address was received. My colleague changed the IP address in the DC's DNS, but when I ping it, a timeout error is received. I know that I should have read a lot more before doing this. What can I do to fix it? Thanks, in advance, for your help!

Update
MarkM, thanks for the info on demoting a DC. That's one of the things I want to do after everything is working. Is there a good, clear article you recommend?

Rusty, there are no DMZs involved at this point. I need to set up a DMZ, but that's another project.