editing grub

[tommy mcdurmon]

I need to edit grub file. I can get to 
 /boot/grub/menu.lst
using the run command, and do the typing to edit the file but cannot 
save the file. A notice comes up saying it is not possible to write to 
this file and there may not be enough disk space.
When I go to options, it allows me to open in terminal but permission is 
denied to list or edit the file.
How can I change this or is there another path to this file that will 
allow me to edit?

thanks
tom