If you are having problems with automatic Nvidia video card driver updates with Windows 10 like I have,
you may want to check the message below I received from Nvidia:
please visit the below link for instructions to turn off driver updates on Windows 10.https://support.microsoft.com/en-us/kb/3073930
Some video cards use WDDM 1.3 and others use WDDM 2.0; Windows 10 supports only one WDDM I am told.
If both types of cards are on your system only one set will work.
San Jose, CA