Replacing older Server hardware Windows 2003

I am looking for a steps to do this. I have a new Dell server hardware.one hard-drive.80gig SATA.
Purpose of the server is to run this application: small set-up of 31 PC-s using A+ education software http://www.amered.com/index.php
The old hardware is running Windows Server 2003 SP1 - I have the disks for Windows Server 2003 R2. What would be the smoothest switch over plan. 1)install the Windows2003R2 on the new hardware - and pick most of the extras POP3/Application/DHCP - if I use them or not.
2) Then to get the active directory and application over??
Thanks again for all assistance. I work a lot on non-server Windows PC-s. Not very much on Windows 2003 Server OS.
Russ@ed-dev.org