Ubuntu Karmic 9.10 and NVIDIA GeForce 6200 - Black screen on startup

I enabled third party driver for a graphics card NVIDIA GeForce 6200 via Hardware Manager on Ubuntu Karmic 9.10. The recommended restricted NVIDIA driver v. 185 caused black screen of death on startup because of an acpi error (cat /var/log/Xorg.O.log). I fixed my problem in this way (if you installed third party driver and didn't reboot yet, just jump to step 7):

1. Select recovery mode in GRUB boot loader to prevent loading of your graphics system.
2. Log in with username and password and then type: cd /etc/X11/
3. Now type: ls to check if xorg.conf exists (karmic doesn't create it during setup). if it doesn't exists, execute this command: sudo nvidia-xconfig to create a basic xorg.conf
4. Modify xorg.conf with nano. Type: nano xorg.conf
5. Find this line: Driver "nvidia" and replace it with Driver "nv". In this way Karmic will use its own driver and not the third party one.
6. Restart your graphics system: sudo gdm stop
7. Run a terminal and type: sudo nvidia-xconfig --nvagp=1 to create /etc/X11/xorg.conf with NVIDIA's agp enabled. You don't need to reboot your pc.
8. Type in the terminal: sudo /etc/init.d/gdm stop
9. Log in and type sudo gdm stop
10. Now, hopefully, your pc should use nvidia driver

I discussed the matter at Ubuntu Forums.

Best regards