If I could get past this driver problem then I think the rest would fall into place.
The windows operating system needs an STMicroelectronics driver installed.
'DfuSeDemo.exe' installed for me in a folder that also includes a 'Driver' folder,
in which are folders for Win7-10, in each of which are subfolders for x64 and x86 (AKA 32-bit).
In each of those driver subfolders is an installer .exe
Run >>only<< the one that matches your Windows version and bit-depth.
Alternatively:
* right-click on "My PC" icon, select 'Properties'
* select 'Device Manager'
* attach and turn on nanoVNA, open:
> Ports (COM & LPT)
* select the appropriate COM port
- if you do not know which one, simply turn nanoVNA off/on to see which disappears and reappears
* right-click and select "Update Driver Software..."
* browse that back to the DfuSeDemo.exe installation folder
Oristo