I am running VirtualBox on a WinXP Host with an Ubuntu 7.10 Guest. The screen resolution problems are well documented, but I have installed the Guest Additions. Now, I need to edit the /etc/X11/xorg.conf to allow me to up the resolution. However, when I try to use Gedit to edit this file, it allows me to make changes but when I try to save them, it gives me the following error message:
You do not have the permissions necessary to save the file. Check that you typed the location correctly and try again.
How do I edit the file? Do I have to use the terminal? Any help would be very much appreciated, especially as I am fairly new to Linux.