Copying User Profiles

I have a small home network w/ one Win2K server acting as a domain controller. The server got badly hacked (don’t ask…), and I had to rebuild the domain. My user account in the old domain was OldDomain\Nathan, and is NewDomain\Nathan in the new domain. When I went to System Properties/User Profiles to copy the old profile to the new account, the old profile was listed as “Account Unknown” and was greyed out, so I couldn’t copy it. I guess my question is, how can I copy user profiles between domains?