Need advice removing a Domain Controller

First make sure the DC you are removing does not hold any FSMO roles. Here is a quick rundown on that:

http://www.petri.co.il/transferring_fsmo_roles.htm

Also make sure the other DC is a catalog server as well. Make sure that the users who logged in, were ACTUALLY logging in using the other server, and not just using cached credentials. From a command prompt on the client run echo %logonserver% to be sure.

The DNS setting for the DNS server should be it's own IP and the secondary should be the other DNS server, correct?

@sysreg2000.  Already done.  Thanks

Yes.

You need to verify that client's settings have those entries as well.

I have minimum DNS experience, but I noticed what I would think is a "big" problem.  Both our DNS servers have a subnet of 255.255.255.0.  One of the computers I checked is 255.255.0.0.  This is "BAD" right?

How would this happen and how do I correct it before I DCPromo the DC?

Hope you guys return to this post tomorrow.  :-(

Just change the subnet mask on your client.

Maybe somebody accidentally forgot the 255 on the third octet or the DHCP scope is misconfigured.

DHCP is set to 255.255.0.0, should I leave that and change the servers, or leave the servers and fix DHCP?

won't a reboot of the clients do the same?

A reboot will provide you the same result.

What kind of errors did you users get when the DC was down?

Thanks to all