I've never tried this but I would think that you could export the keys from your registery that LS changes before it changes them. Or use notepad to modify the exported files to what you want the to be. If things go bad you should be able to import the keys from the recover console. This was possible from DOS mode in win9x so I imagine the feature would exist in XP.

Do a search on MS Technet for backup and restoring the registery for detailed instructions and commands.