Well HCE do this hoping it will help you:

Enter Terminal in root mode: (You know the sudo -s & password thing)type
rm -rf /system/library/extensions/NV*
rm -rf /system/library/extensions/Ge* (those commands are to remove files) also do
rm -rf /system/library/extensions/Natit*

after that install the Universal Nvidia Installer from Zephyrot
now in the same terminal
cd /system/library/extensions/ && chown -R root:wheel * && chmod -R 755 *
diskutil repairpermissions /
reboot

After that ill kill myself if it dont work :-) Hope it helps