My World
You need a purchased serial number for Premiere Elements 12 installation and activation.
When you installed Premiere Elements 12 in the first place, your registration should have been automatic and simultaneous with the Sign In.
If that was the case, then go to the Adobe web site, sign in with your Adobe ID and Password, go to the Search field at the top right of the Adobe home page, type in My Products. Then follow the My Products link to where you should run into Adobe Premiere Elements 12. Click on Adobe Premiere Elements 12 to reveal your purchased serial number.
What do you have for the install - installation files from a purchased online download or installation disc from box packaging of the product?
Please let us know the outcome.
Thanks.
ATR