If you mean you overclocked the card, and the video driver stopped responding and crashing Leaf89.
And now it does it all of the time as soon as windows has loaded up.
It is because the overclocked settings have been retained and are loading just after windows os has on your system.
You will need to remove the Nvidia video drivers from your system.
You will have to do this by selecting safe mode of windows so the Nvidia driver does not load.
Safe mode of windows only uses the core set of drivers that windows has, therefore the card will not crash.
You then uninstall the Nvidia drivers in windows via the programs and features option in windows safe mode.
Restart the system after you are done.
Then you will need to install the Nvidia video drivers to reset any overclocked values you applied to your GTX 960 card in respect to the speed the Gpu was set to and the memory speed of the card also.
Once done it will stop your system from crashing after windows has loaded, or when you play or launch a game Leaf89.
Any overclocking settings you set, are retained and re loaded each time windows os loads.