Ubuntu screen resolution 1680x1050
 

This procedure allows Ubuntu to use the screen resolution 1680x1050.

With Ubuntu shut down, under your VM settings in Parallels, add the resolution 1680x1050. Make sure you check the box "Enable custom screen resolution".

Restart Ubuntu. Open up a terminal. From there, type the following:

sudo gedit /etc/X11/xorg.conf

You'll need to enter an administrator's password here. You should be presented with a text window with a bunch of stuff. Ignore most of it, but look for the following:

In Section "Monitor":
HorizSync 28-51
Change that to:
HorizSync 15-65

In Section "Screen":
Modes "1024x768" "800x600" "640x480"

That'll appear several times throughout the file. Each time you see it, add your desired resolution (in your case, 1680x1050) so that it appears like the following:

Modes "1680x1050" "1024x768" "800x600" "640x480"

Save the file. Quit terminal and restart Ubuntu. That should do it.

Bob