You may follow the steps when it is required to Move Exchange Server 2003 to New Hardware
1. Before you begin, ensure that you have the full backup of storage groups and SRS database of your existing mail system.
2. Disconnect the current email system from your network.
3. Reset Account : Reset the existing computer account from Active directory Users and Computers (Right Click the computer name and select Reset)
4. Install OS in exact patch level (New computer should have the same operating system as the existing one) and bring it in the network.
5. Make sure that the new Computer should have the exact Computer Name as the old one and Join the computer to the domain
6. Login to the new computer with Exchange 2003 Full Administrator account
7. Install exchange 2003 Pre-requisities such as NNTP, SMTP, WWW etc..
8. Configure drive leters on new computer exactly as the old one, with sufficient space
9. Run Exchange 2003 Setup with the switch Setup /disasterrecovery
10. Make sure that Action-Disaster Recovery for the Messaging and Collaboration services and Exchange System Management Tools is checked during setup
11. Ensure to install the Exchange 2003 service pack that was installed on the existing server by using the /disasterrecovery switch after completing the setup process.
12. Check registry and whether the registry subkey exists:
If the subkey does not exist, add a DWORD value and the following hexadecimal value, based on the service pack installed:
DWORD value name: ServicePackBuild
Hexadecimal value: number
Without any Service Pack: 1B20
for Service Pack 1 is 1C3A
Service Pack 2 is 1DD6
13. Install Exchange 2003 post-service pack hotfixes that were installed on old system
14. Restore the storage groups and the Site Replication Service (SRS) databases
15. Once restoration is completed mount all the stores and make sure that clients can connect and that mail can flow.
Note: If there is any IP address change to the new system from the old system, make sure to update DNS records.