I want to restore a satellite pro L450D to factory settings

If you no longer remember the password that you entered when you set up the computer initially, that is a serious problem or impediment. You'll need to get into the administrator account with the stored password to recover to factory settings. Otherwise, a clean install of the windows operating system can be performed with the key printed on the sticker on the laptop, from a disc for windows, but it may stop you from doing that unless you have a full version of the windows install disc, and you have a formatted drive that is blank.