When you try to install a Windows 2000 Service Pack, you receive:
The system must be restarted before installing the Service Pack, to allow some prior file update operations to complete. (These operations were previously scheduled by some other install or uninstall operation.)
If you installed a device or program that set the PendingFileRenameOperations key and you failed to restart Windows 2000, restart the computer so that the PendingFileRenameOperations que is cleared. After the restart, install the Service Pack.