Hi Bella
I've been doing Windows Admin work now for over a dozen years and I would HIGHLY recommend a NEW install of Server 2003 and not do an upgrade if at all possible. When you upgrade you bring in all the trouble and trash of the old Registry and mis-behaving applications.
I know a clean new install is costly both money and time wise but you will be much better off in the long run (IMHO)
I have not done an "upgrade" to a Server now in over 5 or 6 years as myself and others just got tired of the issues it brought with it. A clean install is the way to go.