I have a similar issue here:
http://www.displaylink.org/forum/sho...9&postcount=10
This other thread looks to be the same issue:
http://www.displaylink.org/forum/showthread.php?t=62267
Seems like the commonality is NVIDIA drivers with the 7.4 M2 software. For me, 7.4 M0 still works (under Windows 8.1) as expected -- link here:
http://displaylink.com/support/sla.php?fileid=98 This is a temporary workaround until DisplayLink sorts out their NVIDIA bug...