Quote - when i reinstall poser do i just copy/paste my current runtime folder within the new installation?

That will work fine. However it might be safer to copy your backed-up runtime to somewhere else on your newly installed disk, and point Poser to it. This will avoid overwriting anything important - and if your current library is all in one runtime, Poser might start up faster like that.

If you've saved any render settings, don't forget to back those up as well. I lost all my render presets last time I reinstalled, I forgot about them because they aren't in the Runtime. :( I can't recall exactly where they're kept, but I can look it up once I get home, assuming nobody else chimes in meanwhile.