Hi Dan - thanks for your question. I am going to move it to the Licensing & Installation community where it will receive greater visibility in the subject area. The Member Resources community is primarily for general community questions and suggestions.
Thanks for moving to the correct forum. I may have solved this - for anyone else with the problem and also for anyone's comments as to whether this might cause any problems, this is what I found:
Installed a new Hasp driver from this site: Sentinel Downloads
The re-ran the license installer, and the key LED did not turn off, it completed without any errors, and Pads schematic opened with no licensing errors or warnings. Hopefully this will hold. I'll re-post if I have any problems.