This generally happens if the driver has become corrupted, in such case, you have to uninstall the driver and then search for an updated driver and install it and restart your computer. The steps mentioned below will help you to perform this task.
Step 1: Open Device Manager, search for the Display Adapter click on it to expand, and then right-click on it and select uninstall.
Step 2: From the control panel, search for the option add or remove program, click on it and search for the option Display adapter and click on it to uninstall.
Step 3: Then you have to visit the following webpage
http://www.nvidia.com/Download/index.aspx?lang=en-us
And install the latest display adapter. And then restart your computer.