I'm glad you solved your problem.
For future reference the version of XP does not affect the fixboot and fixmbr functions. They are capable of finding and restoring the boot sectors of any/all Windows operating systems up to and including any version of XP. Vista and the eventual Windows 7 would of course not be included as they use a different boot manager, but the same logic applies to them, they are capable of restoring boot sectors of any Windows from their current release and earlier.