Hi I installed both Windows XP and Linux Debian in my mother notebook and i setted linux as default as i wanted to learn to use it.
Now she got it back, but even if I tried I cannot change default OS; I looked for help in forums and online guides, but nothing I tried worked: it says "Permission Denied", and I was logged as root.
I also tried to reinstall XP, but obviously it doesn't change grub's settings...
Can u help me change it, or solve it someway?

Thanks a lot for attention

I know that you can select which linux version you boot to in your grub.conf file. That file is located in /boot/grub. I'm not sure if this works with windows though.

Once you're in the grub.conf file I think it's as simple as changing the default=0 line.

Good luck, and let us know if that works out for you.

There are two ways to change the default; both involve editing /boot/grub/menu.lst.

Near the top of the file, there is a line: default 0. Since grub numbering begins with 0, that means that the first OS listed is the default. To change that default,
a) count down to the OS you want to be the default (counting from zero) and change the default line to that number.
b) cut and paste the one you want as default to the top of the list, and leave the default at 0.

You must be root to edit menu.lst, and the write permission bit must be set.

Thx a lot for your answers , I already tried to change in /boot/grub/menu.lst, after "su root" and psw, it changes user but then it says "permission denied"... maybe I did something wrong with command line?
How must I set write permission? Sorry for ignorance
and thx again!

use "su -l root"

for further info on su "man su"

Thank you.
I tried, but "Permission denied" again...

I would really hate to be a simple minded person, but couldn't you just chmod the grub.conf file? since there is a link from the /boot/grub/menu.lst to the grub.conf file.

depending on the distro you use....
I will usuall run

$sudo cp /boot/grub/menu.lst /home/*USERNAME*/Destop

this moves it to the desktop so you can edit it easily with gedit. Once your done run

$sudo cp /home/*USERNAME*/Destop/menu.lst /boot/grub/menu.lst

Note that if you are running fedora you will need add yourself to the sudoers list

thx but as I said, I can't have access to /boot/grub/menu.lst, even if logged as root user...

I run debian, I will try and tell you
thx a lot anyway

Run 'ls -l /boot/grub/menu.lst' and post output for us.

to (00):
I did as you suggested, it opened for me a *menu.lst [sola lettura] ( /Desktop) - gedit , reading only....
What should I do?

to Emerson:
output is
--rw-r--r 1 root root 4135 1988-01-02 21:26 /boot/grub/menu.lst

Either your /boot partition (do you have separate /boot partition?) is mounted read-only or immutable flag is set.
Please show us output of 'lsattr /boot/grub/menu.lst'

edit the menu.lst file you have on the desktop, (hightlight the operating system you want the system to default to first as well as all of its settings, cut and paste it to the top of the list)

For example, if I wanted Windows on top, the section might look like this >

title Windows
rootnoverify (hd1,0)
chainloader +

(It might look different, just make sure to get the whole thing)
Once it looks the way you want, run >

sudo cp /home/*USERNAME*/Desktop/menu.lst /boot/grub/menu.lst

reboot to test.

to Emerson:
------------------ /boot/grub/menu.lst

boot partitions should be separated, partion magic when I installed...

to (00)
I have after ## ## End Default Options ##

title Debian GNU/Linux, kernel 2.6.18-4-686
root (hd0,1)
kernel /boot/vmlinuz-2.6.18-4-686 root=/dev/hda2 ro
initred /boot/initrd.img-2.6.18-4-686
savedefault

again for single user, then

### END DEBIAN AUTOMAGIC KERNELS LIST

# This is a divider, added to separate the menu items below
from the Debian
# ones.
title Other Operating Systems:
root


# This ebtry automatically added by the Debian installer for
a non-linux OS
# on /dev/hdal
title Microsoft Windows XP Home Edition
root (hd0,0)
savedefault
makeactive
chainloader +1


Please tell me exactly what I should modify, could I copy and paste something so clearly set apart?
thx for the help...