So is the serial number you're suppose to enter after install the one that came with Poser 5 or Poser 4? I entered the one for Poser 5 and it accepted it, as far as I know. It created some challenge code which was a bunch of words. I don't have an internet connection on that computer so I sent my info by email. I didn't include the Poser 4 serial. Was I suppose to? I have a Poser 4 serial and a propack serial. When I filled out the screen, it didn't ask me for the Poser 4 serial unless I was suppose to type that instead of the Poser 5 number. Kevin