In re: Cakey's experience, sometimes when upgrading (or even updating other drivers on my system) I end up with similar results -- one monitor doesn't get a signal to power up and stays in standby mode.

My fix has been to remove stale USB devices with a tool called USBDeview. Basically, I unplug the DisplayLink hub, start the tool, remove all the DisplayLink devices, including the USB 2.0/3.0 hub parts and Ethernet adapter, reboot, and replug hub after reboot. At that point, the re-enumeration happens and all the devices get configured again from scratch. Just figured I'd mention that for those having issues.