There's a group on Yahoo called Pfaff2170machine. There are quite a few people that have solutions to this in some posts. There is also Pfaff-Talk. Someone got help in getting the old PCD software running. The Yahoo group you would have to join to even read, but Pfaff-Talk you can read.
I just kept a separate XP computer for embroidery only. It's offline, so security isn't a problem.