If you are getting this error you will be getting a black screen and a mouse pointer only. This will be the same even if you login to safe mode or low graphics mode.
Here is the fix:
If you have another OS installed in the system (you have a multiboot system):
1. Log-in to your computer using another OS (You can use Hiren’s Boot CD/DVD or Ubuntu Live Disc).
2. Locate the root directory of your computer (that disk or partition in which you installed the OS that you can’t open).
3. Locate and open the “windows” folder.
4. Locate and open the “system32” folder under that “windows” folder.
5. Locate and open the “config” folder.
6. Rename Default to Default.bak, Sam to Sam.bak, Security to Security.bak, Software to Software.bak, and System to System.bak
7. You will see a folder named “RegBack”. Open it and copy all of its contents to the “config” folder.
8. Restart the computer and you display should be back.
9. Update the drivers from Nvidia’s site.
10. You’re Done!