Step 1. Verify that the NNTP, SMTP, WWW and ASP.NET services are installed and enabled on the server. (see How to enable NNTP service and SMTP service)

Step 2. Install Windows 2003 version of the Windows Support Tools. (download Windows Support Tools)

Step 3. Run DCDiag to test network connectivity and DNS resolution. Review the DCDiag log file you specified for any errors or warnings.

Step 4. Run NetDiag to test network connectivity. Review the NetDiag log file for any errors or warnings.

Step 5. Run ForestPrep to extend the Active Directory schema for Exchange Server 2003. (your account must have the following permissions: Enterprise Administrator, Schema Administrator, Domain Administrator and local machine administrator)

Step 6. Run DomainPrep to prepare the domain for Exchange 2003. (your account must have the following permissions: Domain Administrator and local machine administrator)

Step 7. Now You can run \setup\i386\setup.exe to install Exchange Server 2003.