I'm trying to active Acrobat 9 Pro

I had to upgrade to a new computer, because my old one died. I installed Acrobat 9 Pro, and I've entered the product key that I got under my account on Adobe's website. I enter that into the activation screen, the next screen says that this is an update code from a previous version. The problem is, my old computer is completely dead and I've been using this version for so long that I can't remember what version I upgraded from. I started a chat support session, and when I gave them both product keys, they said there wasn't chat support available for this product, but they couldn't tell me which product it was. I've tried just selecting the different versions that were listed in the activation screen, but nothing works. Anybody have any ideas?