Thank you both for the information, it is somewhat baffling as I've installed and run the software on several systems without issue - PF3 doesn't even need to be running for it to start up.
Could you please try one more thing?
Open a command window (Windows-R, then cmd), navigate to the directory where it's installed and run it manually (.\PF3WebDisplay.exe); hopefully you will get an error message - I suspect that one or more of the .NET runtimes is missing, we just don't know which one.
Thanks,
Martin