Several posters in this thread have noted various approaches to "Moving an Exchange Server to a New Computer That Has the Same Name". If it's useful, the MS Knowledge Base article KB155216 by that title (last reviewed by MS 1/31/2003) has extensive details on the approach Fuego007 has helpfully summarized in his post.
I used this info to move Exchange 5.5 SP4 from an old single processer NT 4.0 server w/ 2 logical drives, to a dual Xeon processer Win2000 server w/ 1 logical drive. Key "tips" based on that experience:
1. Read the "qualifiers" in the KB article carefully. I found it very helpful to read the article several times before beginning, highlighting key sections, and crossing out sections that didn't apply. Note that the article differentiates between using "Online Backup" and "Offline or File Copy Backup" options and you'll need to think through which option you want to use. I used the offline backup option.
2. Document the configuration info VERY carefully. (I caught a typo in the existing site directory name which had to be replicated exactly in the new install!) Also, be sure to record the old Exchange anti-virus settings (see 9 below)! And, have your Service Pack(s), Anti-virus software, and any Exchange backup agents all downloaded and ready to install before you start.
3. If you do offline defrags before moving priv.edb, pub.edb, and dir.edb files, consider using the /p option to retain and preserve original uncompacted databases on the old Exchange server, so you have a fall-back option.
4. Test each database for consistency, don't continue until Eseutil reports State: Consistent.
5. The Internet Mail Connector will need to be deleted and reinstalled in Exchange after the move, or you can do a registry hack to enter the correct domain name.
6. Follow very closely the steps in the KB article describing exactly when to rename and when to shut down the old Exchange server (you may need to bring it back up if a problem occurs!)
7. Be sure to use the Setup.exe /R to do a stub install of Exchange 5.5 on the new Exchange server.
8. Remember to allow time to re-install any backup agents and the anti-virus software, and use the same service accounts for these that were used on the old Exchange server.
9. If you are intalling GroupShield SP2 on the new Exchange, the "On Access" settings you select will also be applied by default on the entire information store you just moved when an "On Demand" scan is run the first time on the new Exchange server. Call Network Associates to discuss this in advance, because this can suddenly put thousands of e-mails previously accesible to users in "Quarantine" unless your new GroupShield settings aren't carefully implemented based on the old Exchange settings.
I hope at least some of these "tips" are helpful!