Just for info, the Lightroom 4 key HAS been registered to my account, so it should show in the my-products area, but it does not, same with my LR 5 serial
Sorry to say but there is no way to retrieve your serial number if it isn't under your products in your Adobe account.
That is why you have to make back ups of the serial number, Print it out, make backups of the email it came in, make backups of your computer.
About the only option now is to re-purchase LR 5 to get a new serial number.
Thanks, i understand i should have made a backup,
My question/point is how can my licence have disappeared from this section, more-so with the lightroom 4 licence (which i have the email for) but its not on the website either.
If you purchased LR5 from the Adobe web site via ESD, then your purchase should be under "My Orders". This contains the invoice and serial number.