Please refer to item (f) almost at the bottom of my Help2Help-post (which i.a. has a link to the update-page).
(If you still have the email with the code e.g. re-forward it to yourselves, making sure to select only "send" and NOT to (also) "receive" e-mail, so that you will be able to simply pick it up again after you've reformatted your HD. Instead you could - of course - also save the email to a removable medium prior to formatting.).
(If you don't have the info needed anymore, I would advise you to contact support
(link in item (f))