As in what? You need a USB drive of some sort to back up saves etc with, i would take all demos/psn games/vids etc off the system so it makes the backing up easier. Once the backup is done, de-register all the users from your console then remove them. You may have to make one account so you can delete the proper ones then remove this, once done format the HDD. If you have both consoles at the same time you can use the ethernet cables and do a backup that way, this seems to be the better option if you can do it.