Virtual memory is what Windows uses if you don't have enough RAM to do the job. Curious labs says one possible way to get rid of the Insufficient Disk Space error is to adjust your Virtual Memory. However, I've been told Windows XP does a good enough job on its own. I don't like fiddling with such intensive settings. I always wanted more room for Poser, so I got a 120GB hard drive, and gave it all to Poser. I almost never got that Insufficient Disk space error again. When I did, I defragged.