PREPARING THE SERVER ENVIRONMENT FOR EXCHANGE
Before installation (or upgrade), Windows 2000 Server must be patched to at least SP3. The following services must be installed and running: WWW Publishing Service, SMTP Service, ASP.NET, .NET Framework, and NNTP Service.
Exchange Server 2003 requires at least a Pentium 133MHz (733MHz is recommended) compatible computer with 256MB RAM (512 recommended), 500MB on the volume where Exchange is installed, and 200MB on the system volume. Disk partitions must be formatted with NTFS.