MIMO 710S works on 1 vid card, not another

[SusiBiker]

Hi JamesH,
Hope you can help...

I was running an ATI 5850 HD a while ago, and was having no issues.
I uninstalled the DisplayLink drivers, then -
I uninstalled the ATI drivers & software, shut down the PC, and fitted an EVGA GTX 770. The DisplayLink device was not connected.
I installed the NVIDIA drivers (can't remember which), and all was fine with the PC for a couple of months.
Yesterday, I decided to press an old monitor back into service using my DisplayLink adapter.
Plugged in the adapter, and Windows Update installed the latest drivers...

DisplayLink Software Release: External Release Note
Software Package: DisplayLink Graphics
Product Version: 7.6.55705.0
Product Date: 5th June 2014
DisplayLink Core Software Version: 7.6.55673.0
DisplayLink Core Software Date: 1st June 2014
DisplayLink DL-3xx0 / DL-5xx0 Firmware Version: 8.8.11.63470
DisplayLink DL-41xx Firmware Version: 8.8.11.63472

And there the fun began -

I get multiple crashes on startup and shutdown of nvlddmkm.sys -

The description for Event ID 14 from source nvlddmkm cannot be found. Either the component that raises this event is not installed on your local computer or the installation is corrupted. You can install or repair the component on the local computer.
If the event originated on another computer, the display information had to be saved with the event.
The following information was included with the event:

\Device\000000da
CMDre 00000000 00000080 00000000 00000005 00000010


And sometimes a few of these thrown in for good measure -

The description for Event ID 1 from source NvStreamSvc cannot be found. Either the component that raises this event is not installed on your local computer or the installation is corrupted. You can install or repair the component on the local computer.
If the event originated on another computer, the display information had to be saved with the event.
The following information was included with the event:

NvStreamSvc
NvVAD initialization failed [6]


This means that the PC will hang (blank screens) for about 5 minutes before shutting down, and will hang (blank screens) for about three minutes after the login screen appears.

I am running Win7x64Ult and have updated the NVIDIA drivers to the latest -
337.88-desktop-win8-win7-winvista-64bit-international-whql.exe
and the problem is still there.
As soon as the adapter is removed - I get a working PC back again with no crashes.

All drivers on the system are the latest, and I'm now at a loss of how to proceed.
Any ideas?

Regards,
Susi xx

EDIT:-
Even with the DisplayLink unplugged, the errors continue - It happens when the screens are blanked (instead of a screensaver). The rate is about once every four seconds.
The only way to stop it is not to allow the monitors to go to sleep, or uninstall the DL drivers.