Start Logbook Pro and choose FILE...ARCHIVE...BACKUP or FILE...BACKUP, depending on your version, and save the file. If you receive a warning or error when trying to save the file to your USB drive then save the file to your hard drive and copy it to the USB drive.
Another way to backup is to save the file to your PC and then email to your web based email or work email.
NOTE: You cannot backup directly to CD media.
To restore a backup you simply start Logbook Pro and choose FILE...ARCHIVE...RESTORE or FILE...RESTORE and tell Logbook Pro where to find the .bak file and then where to save your logbook.