I have Win7, 64 bit with PSP7, PSPX and CS4 which are all running with no problems. *edit* my PSPX version 10.10
I have automatic updates from Impulse TURNED OFF. (lessons learned)
in the future you might think about using a restore point rather than uninstalling then reinstalling programs. Seems to be a much easier and more safe method to remove recently added errors.
Not sure its a bug mate,paintshop pro x is not compatable with windows 7
there are four uploads from corel to modify the original program to make it compatable with vista/win7 and it works.