Thank you Brendon, a very useful piece of advice indeed, and kind of you intervene.
I have learnt from bitter experience over the years to always uninstall earlier versions of programmes (via Control Panel) before installing the new. I make sure to tell family members, friends etc. to do the same, rather than merely deleting the programme files via File Explorer.
I do not usually participate in forums, but I am a long-time user of PCs, and earlier computer systems (my first was a Commodore 64 around 1982) and am now in my late 70s. Nonetheless, it is refreshing to know that there are experienced people out there imparting their knowledge and experience. Keep up the good work, it is appreciated.
Incidentally, my NXTPro8 is working fine.