There are circumstances after you have performed an emergency repair operation that do require the reinstallation of a Windows 2000 service pack.
When you install a Windows 2000 service pack, the %Systemroot%\Repair folder is not updated, by design.
If you installed Windows 2000 from a slipstream of the latest service pack,
ServicePackSourcePath points to the latest Service Pack and HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Setup\SourcePath point to a slipstream of that service pack
you DO NOT have to reinstall the service pack after a repair. In all other cases, if the repair replaced system files, you must reinstall the latest service pack.
NOTE: When you install a servie pack, you MUST update the %Systemroot%\Repair\Regback folder by using the Emergency Repair Disk feature of NTBackup and checking the Also backup the registry to the repair directory box.