A simple solution for Windows problem = 10 oz sledgehammer.
Just kidding.
You can reinstall Windows 2000 and use the other name, and in matter facts you still can access to your old user folder.
Or use the good old file checker, which it can be run off the command.
Insert your windows 2000 CD in and click [Start > Run]
type " cmd" and press enter. A command prompt appears. Make sure you did put the Windows 2000 cd in it and leave it there.
type " sfc /scannow" and press enter. It is going to take a while for them to scan and replace the files.
After that, reboot and the file missing errors should stops.
Thank you for coming in here, katti36!
Regards Lucan