Users who have purchased a QT 7 Pro registration key from an online Apple Store are advised to store copies of their registration information (i.e., registration key and account name used for purchase together with any salutation if used) to alternative secure locations while it still may be available. Users having made their purchase in excess of 18-24 months ago will probably have to locate their original "Confirmation" email from Apple to obtain this data. Data for purchases made 18-24 months ago may or may not still be available from Apple but will likely require your contacting Apple by phone since Apple Store Account user acccess to this data is now supposedly subject to an 18 month limitation window for accessing your online "Order History" list. See Article HT2376: "QuickTime Pro Key: Retrieving a lost key," dated June 06, 2012.
User "Formula4G" indicates that although his QT Pro key purchase was made less than a year ago, he is unable to retrieve lost or missing QT Pro Registration Data from his Apple Online Store Account "Order History" area per instructions given in article HT2376. Request anyone else having the same problem immediately bring this issue to Apple's attention via QT Product Feedback.