Outlook Archive Unopenable

Had Win2K OS and Office 2000 Pro. Was upgraded to Win XP and the supposedly backed up personal folders will not open now. Our techs have tried everything THEY could think of, but it appears I’ve lost 122MB of info due to some corruption in the .pst files. ANYONE out there have a clue on what we can do to recover this info?? We’re WAY beyond the normal options.