FlashBack has separate installations for each edition to allow users to install different editions side-by-side on the same PC.
Since FlashBack licence keys are specific for a particular edition, this means that you will then to install the edition that you have upgraded to. For example, if you upgrade from FlashBack Express to FlashBack Pro 5, you will need to install FlashBack Pro 5.
If you log into your account at https://secure.blueberryonlinestore.com/Login.aspx, you can download any edition of FlashBack that you have a valid licence for from the Download Product page - this will automatically update to display the correct links specifically for you.
Once you have installed the version that you have upgraded to , you will be prompted to enter your licence key when you first run FlashBack.
(Note - when upgrading a version 1 - 4 licence, you will be issued a new licence key but for version 5 and onwards, the existing licence key will continue to be used)