We have a bunch of old (read that as: OLD!) personal designer files. The Knowledge base didn't give me much hope but I figured I'd reach out to the exploder to see if anyone knows of a way to convert or directly open them in Creo 2.0.
PTC had, at one point, a translator, PDtoDXF, on their web site. I believe the PD file has to be at least a version 5 file.
Personal Designer can also be found on the web. I have it running on a VM with Windows 98. I use it for for just this purpose. I open the old files and save them to the newer file. Then use the translator to create a DXF file.