Sounds like the "Offline Files" database in Windows 2000 is corrupt. One of the features in the new operating system is that it can cache files you've accessed from a network share. The advantages are that it speeds up the time it takes your application to access the file, and the file is available even if the network share is no longer available (in other words, the network or server is down).

Unfortunately, the Offline Files feature is a little buggy, and the database that keeps track of the cached files can become corrupt. The first step is to delete the cache, so Windows and your applications will have some room on the hard drive to work with. You could manually delete the files in the C:\Winnt\CSC folder, but it is not recommended. Follow these steps:

1. Open up Windows Explorer (<Windows Key>+E or Start--Programs--Accessories--Windows Explorer)
2. Click on the Tools menu and then Folder Options...
3. Click on the Offline Files tab
4. Click on the Delete Files... button
5. Click the OK button to delete all the cache files and take a coffee break while the files are being deleted
6. Click the OK button again to exit out of Folder Options

Now that you have acquired your hard drive back, here's how you reinitialize the Offline Files database:

1. Open up Windows Explorer
2. Click on the Tools menu and then Folder Options...
3. Click on the Offline Files tab
4. Hold down the <Ctrl> and <Shift> keys together while clicking on the Delete Files... button
5. Click the Yes button to confirm you want to reinitialize the database
6. Click the Yes button to restart your computer

Re-initialization complete!