Suse Linux dual boot fix

hi does anyone know how to fix dual boot with Vista being primary OS and Suse Linux Eterprise Desktop 10 as a secondary OS, Also Vista is installed in RAID configuration.

I found some stuff online and basically I have to edit a menu.lst as superuser however the menu.lst will not open even if I type ‘sudo’ and provide the password

the error I get is this:

static-host:/home/andy # sudo gedit /boot/grub/menu.lst

(gedit:14313): Gtk-WARNING **: cannot open display:

anyone has a simple solution, please

edit: also how do you become a super user?