I'm still having problems with my Mach3 not communicating with the parallel port so I tried to reinstall Mach3.
When I uninstalled Mach3 I just happened to have the DRO's at values other than zero, now when I reinstall the DRO's stay at the same value. This suggests to me that my uninstall didn't remove everything from my computer.
What do I have to do for a full uninstall? Am I missing some drivers or something similar?

You can check to see if the driver was removed in device manager. It will say MachX pulsing engine. You can also delete the Mach 3 folder that is most likely on your c drive. If you have any profiles set up, screen sets or macros you want to keep, save a copy of those on a thumb drive or CD before you delete the folder.

Brett