Network Expansion

I am the network administrator at a local high school. We currently have a network in which we employ two Dell PowerEdge 4300 servers running Windows NT 4.0. This summer we will be installing two new servers, Dell PowerEdge 4400’s both. I am wondering if when installation time rolls around will I be able to retain the same domain name or will I have to come up with a new domain name. Also any pitfalls to look out? All info is greatly appreciated.