You didn't tell us the size of your hard drive. I don't partition any hard drives. There just isn't any need these days when hard drives are so inexpensive. Besides, you never know when you might decide one partition is too small, etc. The best thing anyone can do is immediately backup any new Poser stuff to CD's. I routinely install all my stuff to a temporary directory, then re-arrange it the way I want. Then I make CD's with the original and new files, and then I install the stuff into Poser. Oh, yes, you really want to backup your Poser installation(s). I have Poser 4 and Poser 5 safely backed up onto CD's Yes, it took the better part of a day to backup the 14.7 GB Poser 4 installation. But it would take several days to reinstall everything if it had been lost! Do you have a special need to have more than one operating system available? I've never had a need to "go back" once I installed Windows XP.