|Thank you both for taking the time to respond. Both copies of Photoshop are legitimate. Photoshop 5.5 was purchased to support an upgrade to 7 (yes, it is old...yes, there are newer versions...yes, I am unable/unwilling to shell out more for what I don't really need). I'm sure GIMP is decent, but it is not Photoshop.|
Fortunately, I solved my own problem - by creating a new user account and sliding all my files over. Photoshop installed just fine in the new partition. It also resolved another niggling little annoyance as well (persistent no disc error).
So, thanks for playing.