I'm well aware of the stupidity of trying to demote DC that is also an Exchange 2003 SP2 server. We 'thought' between an image and other backups before the demotion we were sufficiently prepared for problems. We were wrong. Currently we have some functionality out of our Exchange box. Mail delivery is working as planned and users are able to log in with Outlook and Webmail as long as they use the FQDN.
We're kind of stuck with where to go from here. Do we attempt to fix the problems we're having (Can't add another mailbox, DNS Zones gone and can't add them to AD, etc) or do we rebuild the box? And if we rebuild the box what is the best way to do so so it's only a member server and it retains it's IP and Hostname?