I tried to disable the integrated HD graphics 4000 so I could use Nvidia NVS 5400M graphics full time, but when I disabled the HD graphics 4000 driver in Device Manager, the screen went black. I tried plugging in a external monitor in the VGA port but nothing happened.
How can I enable this driver again with no screen?
Press and hold the power button to shut down the system.
Restart Windows in Safe Mode by pressing F8 on boot
This will bring up the Safe Mode option, and also give you the option of restarting your system properly, and troubleshoot.
Once you are in Safe Mode, go to Device Manager and enable the driver.