Not sure how it works in 2k, but on my XP machine I can specify different domains at logon. So, for example, there is some sort of network domain at work that connects me to the campus network; I log in with my AFSID. But, I can specify different domains, e.g. I specify the machine I'm on and then connect to one of the usernames I've defined on it.
SO, it may be that all your old stuff is there, but you're not choosing the right domain when logging in. Or, maybe you need to be connected to your work network to do your usual logon, and it will work ok once you are back at work.
I'd be careful about fiddling around with it too much -- let your IT people solve it if you don't know how yourself. I imagine they can work something out for you.