Paul had a Dell XPS computer, then he got an iMac running Boot Camp. He hasn't been backing up since December. He changed the file structure when he moved to the new computer, and now his backups are duplicates instead of a select backup folder. Leo says he can tell his operating system where his home folder is in the partition. Once he's done that, he can delete the duplicates.
He can also try using RoboCopy in Windows. In the command line, he can just type "robo copy" and enter. Leo would also recommend a sync utility like Second Copy by Centered Systems. For the Mac, he can use RSync.