Chris Harper said:
> Try checking the video overlay settings for the adapter. Any
> settings you can modify in regards to this will most likely lead to
> the solution.
This was the closest to the mark. Turns out that the "cloning"
feature of this dual-DVI card does not exactly clone video to both
ports. Only the primary port will play some videos (other videos do
play on both primary & secondary ports, we still do not know why).
When we changed the setting to make screen 2 (analog) the primary and
screen 1 (digital) the secondary, videos then showed on screen 2 but
not screen 1. This is not ideal, but turns out to be good enough to
run our brain imaging tasks as we need screen 1 only for a control
OTOH, some may argue that the dual-port card does clone videos to both
ports, but just not to both analog & digital outputs, that would also
fit our results. We probably will not test this though.
Thanks to all for helping out.