How do I set the correct monitor resolution with Nvidia drivers for a monitor that does not send EDID?

Follow these steps.

Note that steps 6 and 7 are not usually necessary; try skipping them and if that does not work, repeat all steps and include these two. Some monitors don't send EDID information to the computer, so Ubuntu can't know what the monitor is capable of and only offers safe (low) resolutions. Those two steps resolve that problem.

1. Reboot and restart in Recovery Mode.
2. Type rm /etc/X11/xorg.xonf (Enter)
3. Type reboot (Enter)
4. Once you're at the normal Ubuntu desktop again, press Alt + F2 and type terminal (Enter)
5. In the terminal, type sudo nvidia-xconfig (Enter). This will write a new xorg.conf file.
6. Press Alt + F2 and type gksu gedit /etc/X11/xorg.conf (Enter).
7. Look for the part beginning with Section "Monitor"and there enter the correct HorizSync and VertRefresh values. (See How do I look up the hsync/vsync values for my monitor?)
8. Restart.
9. Once you're at the normal Ubuntu desktop again, find "Nvidia X Server Settings" in the "start menu" and start that.
10. In the section X Server Display Configuration, set the desired resolution and press the button Save to X Configuration File.
11. Reboot.

You should now have the proper resolution!

Finally, copy the file /etc/X11/xorg.conf to a safe place in case you mess it up later and need to restore it.