Thanks for the suggestion ChrisB - i unpacked the zip file on my laptop and inspected the results, and the bin file was there and complete with the freecad.exe.
i copied the unpacked freecad 0.19 folder to my desktop, and voila!! it works.
Good work-around, but still curios as to why I can't unpack it on the desktop. Intend to play around and see if I can unpack other Github files on the desktop.
Cheers guys - and thanks chrisB.
