there is also a linux boot disk program called Offline NT Password and registry editor. It loads up a linux shell on boot and lets you access the SAM database where the passwords and account settings are stored. You can enable those disabled accounts or blank out passwords with it and then save the settings, pull the disk, and reboot. I don't know how many times this proggy has saved my butt. I work in a computer store and I get people come in and say that they forgot their password in xp or something and they are using the only administrator account. This works pretty much in any version of nt based systems (NT, 2000, xp) but i'm not sure about w2k3.
More info, docs, and downloads at
http://home.eunet.no/~pnordahl/ntpasswd/