dual-boot GRUB overwritten; cannot boot Windows

[corsinnema]

Previously I had changed the order of my dual-boot GRUB menu so that XP would load by default.
When I upgraded Intrepid to Jaunty, this GRUB menu got replaced with a single-boot menu. The windows partitions still exist and can even be mounted.
Is it possible to restore dual-boot by adding some lines to the new GRUB menu? If so, what do I put?

Any help would be greatly appreciated!

[Bauldronius]

I am a noob in ubuntu but i think this will help
open terminal and type sudo gedit /boot/grub/menu.lst
there you will see a example looking like this
# title Windows 95/98/NT/2000
# root (hd0,0)
# makeactive
# chainloader +1
copy it to the end of the document "without #" where there is the boot menu list
next you will need to find out what to type here: root (hd0,0) so open a new terminal and type sudo fdisk -l and you will get a list looking like this:
Device Boot Start End Blocks Id System
/dev/sda1 1 3647 29294496 5 Extended
/dev/sda2 * 3648 19458 126994432 7 HPFS/NTFS
/dev/sda5 1 486 3903732 82 Linux swap / Solaris
/dev/sda6 487 3647 25390701 83 Linux
for example this is my windows partition:
/dev/sda2 * 3648 19458 126994432 7 HPFS/NTFS
sda2 means (hd0,1) sda1 means (0,0) etc
so what you should end up should look like this in the grub menu file
title Windows 95/98/NT/2000
root (hd0,1)
makeactive
chainloader +1

[zeex]

Previously I had changed the order of my dual-boot GRUB menu so that XP would load by default.
When I upgraded Intrepid to Jaunty, this GRUB menu got replaced with a single-boot menu. The windows partitions still exist and can even be mounted.
Is it possible to restore dual-boot by adding some lines to the new GRUB menu? If so, what do I put?

Any help would be greatly appreciated!

updating menu.lst will work but if you want another approach.

Boot with winXP CD -> go to repair mode -> at the command prompt type fixmbr. (This will update the MBR basically now you can boot XP but not linux). This step is equivalent to removing linux (http://stringofthoughts.wordpress.com/2009/03/29/removing-linux/) from the system.

Now boot with ubuntu live CD and reinstall the grub (http://stringofthoughts.wordpress.com/2009/03/29/re-installing-grub/).

See windows thinks it's the only OS in the world and that's why it removes the linux but linux has a huge heart. It plays along with every other OS :)

Good Luck :)

[Luke771]

Dont do that!
Using the Windows CD to repair the MBR will ... well, overwrite the MBR.
Your PC will boot straight into Windows and you'll have to use Windows own (sucky) boot loader to boot Linux.

Manually adding an entry to /boot/grub/menu.lst is the way to go.
Remember to edit menu.lst as root or you won't be able to save your changes

sudo gedit /boot/grub/menu.lst

IF your Windows partition is on sda1 and your Linux partition is on sda2, add this entry:


title Windows
root (hd0,0)
makeactive
chainloader +1


To modify my example entry according to your own setup, answer the question: "on which partition is Windows?", then modify the 'root' line (second from top) according to this table:

Windows partition.... 'root' line.

___sda1 _______...____root (hd0,0)

___sda2 _______...____root (hd0,1)

___sdb1 _______...____root (hd1,0)

___sdc3 _______...____root (hd2,2)


It's about counting: physical discs first, partitions later.
The A in sda1 stands for first physical disc and the 1 stands for first partition (on that disk).
Therefore, the third partition on the second HDD would be sdb3.
The _first_ 0 in hd0,0 stands for first physical disc and the second zero stands for first partition. The third partition on the second HDD would be hd1,2 (the count starts from zero rather than 1).
In order to boot from sdb3 (third partition of the second HDD), your 'root' line should look like this:

root (hd1,2)

[zeex]

Dont do that!
Using the Windows CD to repair the MBR will ... well, overwrite the MBR.
Your PC will boot straight into Windows and you'll have to use Windows own (sucky) boot loader to boot Linux.



Yeah That's why i told him to reinstall grub after fixmbr.

Although i'm curious how do you use windows bootloader to boot Linux

[corsinnema]

Thanks very much guys. You're full of beans! This improved my day quite a bit. Editing menu.lst worked wonderfully!