There seems to be something wrong. You say the C partition has 5 GB free out of 10, after only having Win2K installed? Another thing that might work, is that perhaps instead of having the SR3 automatically detect where your Poser installation is, choose the location manually instead. I had a simliar situation when Pro Pack's SR3 wouldn't install when it found it automatically, but was happy as a bug in a rug when I located it manually.