photoshop elements 9 - serial number

Hello,
I'm sorry for my english, but I'm from Germany.
Whatever, my question or problem is:

Years ago I bought a tablet (wacom bamboo fun pen and touch medium) an it included an pse 8 (later pse 9) version.
At the beginning i used it regulary but in the last years i stopped using it. In last November my laptop crashed and I had to remove everything, including my photoshop.
Now I wanted to install my photoshop again but I need a Serial number. I can't find it anywhere in the package!
Where can I find it? It is really important. Please help me.
Greetings, Julia