I'd upgrade display driver, if latest uninstall and reboot to reinstall it.
If that doesn't help reinstall the video card checking for debris in slot and connection is tight.
Next run a full scan with Malwarebytes.
Then SFC -SCANNOW Command.
Establish a Clean Boot to make sure another program is not interfering, check the logs and System Resources and work through the other steps in Troubleshooting Steps for Windows 7