2 ways.

(assuming you have the machines networked)

1:  Install Poser on new machine. Copy Runtime from Old Machine to new machine
or
2: Install Poser on new machine. On old machine, Share the Runtime Folder. On new machine Map this to a drive letter (such as X). In poser on new machine connect Runtime on old machine as a Runtime. (warning : this method can lead to long load times as content loads over your network)