Adding windows os to grub
 

Look i am using ubuntu 8.04.Also i have windows vista.These two os are on my primary master harddisk.Now i wish to add windows xp to my boot loader which is grub.But this os is on my primary slave harddisk.
I know that by editing the file /boot/grub/menu.lst it can be done but i don't have or get enough permissions to edit,despite me being the administrator and having all user passwords.Secondly when i try to edit permissions of this file to "read and write" i can't select it that is there is no editing possible in the permissions tab.Its all grey.Plz help!!

Are you using sudo? Whenever you need to edit a system file or do some administrative work, you have to put sudo before the command you're using. It will ask for your password, and then run the program.

Try this on the terminal:

better understanding
 

So you have on your first hard drive-
1)Windows Vista
2)Ubuntu

And you have Windows XP on another hard drive, that you want to add to grub, correct?