the machine is a self build and the only non-stock item is the audigy zs - i say non-stock becuase its old and out of date.

update 1903 is not screamingly urgent so i'll just see if microsoft come through - it maybe that i'm at the tail end of the process with Windows 10 Pro.

thanks for all the advice - as jazzmammal says there are so many combinations that hoping to narrow it down here is a triumph of optimism!