This should be the first choice of methods if available!
The built-in backup function under saves everything including, if chosen, the DVD-Covers. The backup-file can be re-imported with DVD Profiler of the same or a higher version number.
If you still have your old
"\Documents and Settings\$Username\My Documents\DVD Profiler\Databases\"-folder (Windows XP and earlier) respectively
"\Users\$Username\Documents\DVD Profiler\Databases\"-folder (Vista and later)
on a working HDD simply click and open the desired database. You can continue to run the database there or make a backup, open the database "Default" and restore it to your new "\Documents and Settings\" on your new HDD. I would recommend the latter.
If you have uploaded your collection to the DVD Profiler online-list with you can download it in the same manner. The personal data, although not visible in the online-list, is recovered with this method as well. Only self scanned DVD-Cover that weren't contributed to the main-database and cast and crew head-shots can't be recovered with this method.