You need the serial number for Premiere Elements 2 for sure. Not sure what you mean by the activation code. The numbers that you want
are for serial number.
Your only hope of finding the serial number is at the Adobe web site under "My Products" if you ever registered the program.
If the program was registered, then
a. Go to the Adobe web site (http://www.adobe.com), sign in with your Adobe ID and Password, in the Search field type in My Products.
b. Follow the My Products link to My Products page. When you get to that page, look for Adobe Premiere Elements 2 listed there for you.
c. Click on Adobe Premiere Elements 2 to reveal your products serial number.
If that does not work, I know of no other way to get your serial number.
Please let us know the outcome.
Add On...reminder, this is not Adobe, rather user to user.