Ok, so I bought the Poser 8 Upgrade version using my Poser Pro serial number at CP and downloaded and installed it. Guess what? Even though there's a place for putting my Poser Pro Serial number in, since it's an upgrade version, that box is greyed out and it only lets me put in my new Poser 8 Serial number.  Not that I mind only having to input the one serial number when installing it, but doesn't that defeat the purpose of requiring a second serial number for the upgrade version?!?   

This was true of Poser Pro and Poser 7. The Upgrade Code is not needed.

I was wondering about that too.   I also left the box checked at the bottom to register the product as I was installing it but nothing happened.   So I don't know if it's registered or not.

 Yep, that happened to me also.  Sharen

I'm having the same problem here.

Purchased it as an upgrade for Poser 7, after hours of downloading (.......) I finally got the file and installed it. When I open the program it says I must enter my serial number, put in the new one for the Poser 8 Upgrade that I got when I purchased it, but can't do anything.

The box where you have to enter the old serial number is greyed out as well.

Anyone has an idea?

You should not need to enter the old Code.

But what about the registration checkbox?   I left both boxes checked and I didn't see any registration page or anything.  How can I tell if my copy is registered?

The registration is sent directly to Smith Micro... (what you entered there....)

You can also go to Support and manually register

 I noticed that as well. So I put the old code in the next field (company I think it was) just so I had it handy LOL