It is possible that Poser 5 may show up again in 3DWorld, Creative Arts, etc magazines or you can go to PurPlus.net etc,  and see if they still have Poser 5.  Just ensure that your CD recorder player can read it eg if the software comes as a DVD, it may not if you don't have a DVD recorder player.

and you are not alone, Poser 5 has many valueable assets and you are absolutely right, an older computer cannot handle Poser 6 etc, plus if your laptop is running great, tossing it for the newest and greatest is like tossing a flawlessly running older car.  As far as I'm concerned it tain't gonna happen---Jan