Since nobody had taken a crack at this, I will start this off with some suggestions.
To start, if you do have a copy of an disk imaging software, I would recommend that you create an image of the computer in case there is something that your recover attempts may destroy. At least with an image of your computer, you would be able to extract the data using the imaging software - if you use something like Ghost. Since you have been able to login to Windows you are at the point where using the last known good configuration will not help. Although it may be worth an attempt at this point....what do you have to lose... Please see this article for more information - What is the Last Known Good configuration and what can it do to help me?
Another step in the recovery process might be to try a repair install of Windows 2000. The following article explains the process a little further -Windows 2000 ERD and Recovery Console
. Here's another link with some heplful screen shots of the various Windows 2000 installs. You would probably take the "manual repair without ERD". Here's the site - Windows 2000 Professional Install Guides
There are also several options in the Windows 2000 Resource Kit that will give a little more knowledge about the options that you have. Repairing a Windows 2000 Installation
I don't have a magic one line fix that will resolve the issue, but hopefully this will point you in the right direction.
Hope that helps. Good-Luck.