Dual-boot MBR destroyed by Windows Update?

[starfailure]

I dual boot XP and Kubuntu, with GRUB.

I woke up this morning to find my PC on a lovely "Non-system disk or disk error" message.
I emptied floppy and cd drives and rebooted to get the same thing.

Later found out my wife said she ran "Windows update: install updates and shut down" the night before.

Can anyone explain why/how a Windows update might cause this?

What steps do I need to take to fix my MBR and get the GRUB boot loader functional?

Thanks much.

[dstew]

It is a little odd, because if Windows puts its own boot loader into the MBR, usually at least Windows will boot.

If you have an Ubuntu Live CD, boot it. Open a terminal window (Applications --> Accessories --> Terminal) and type
sudo fdisk -lThat should get you a list of the partitions you have. If it looks like all your partitions are OK, then try to re-install grub (see below). If you have doubts about your partitions, post the fdisk output to the forum.

To re-install grub, start the grub shell program by entering grub on the terminal command line. That gets you the grub command line, with the grub> prompt. At the grub prompt, enter this command:
find /boot/grub/stage2It should return a partition name, in grub-speak, like (hd0,1). Your exact number may be different. Whatever it returns use as the argument for a root command:
root (hd0,1)Then, setup grub in the MBR of the first hard drive:
setup (hd0)
quitShut down the Live CD system, remove the CD, and reboot. Hopefully you will see your grub menu.

[starfailure]

Thanks for the great response. I'll try to do this when I get home or later tonight.

[starfailure]

Okay, when I use "grub> find /boot/grub/stage2" from the Live CD, I get File Not Found.

[dstew]

Quit grub. Post the output of the command
sudo fdisk -l

[starfailure]

Disk /dev/sda: 250.0 GB, 250059350016 bytes
255 heads, 63 sectors/track, 30401 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/sda1 1 1081 8683101 7 HPFS/NTFS
/dev/sda2 1082 30401 235512900 f W95 Ext'd (LBA)
/dev/sda5 1082 8730 61440561 b W95 FAT32
/dev/sda6 8731 16379 61440561 b W95 FAT32
/dev/sda7 16380 17653 10233373+ b W95 FAT32
/dev/sda8 17654 20203 20482843+ b W95 FAT32
/dev/sda9 20204 25302 40957686 b W95 FAT32
/dev/sda10 25303 27852 20482843+ b W95 FAT32
/dev/sda11 27853 30401 20474811 7 HPFS/NTFS

Disk /dev/hda: 122.9 GB, 122942324736 bytes
255 heads, 63 sectors/track, 14946 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/hda1 * 1 2198 17655403+ 7 HPFS/NTFS
/dev/hda2 2199 12906 86012010 f W95 Ext'd (LBA)
/dev/hda3 12907 14946 16386300 83 Linux
/dev/hda5 2199 7425 41985846 b W95 FAT32
/dev/hda6 7426 12651 41977813+ b W95 FAT32
/dev/hda7 12652 12906 2048256 82 Linux swap / Solaris
ubuntu@ubuntu:~$

[starfailure]

Honestly, I can't remember which drive has the XP boot part. on it.
I think it's on the IDE.

[louieb]

When you ran grub from the terminal you need to start grub by using

sudo grub
otherwise the find command doesn't work.

destews advise should work then.

BTW. I have heard that XP SP3 does cause trouble for those of us that Dual Boot. Just wondering if thats what the wife updated to.

[starfailure]

I don't know if that's what the update was or not... Could you elaborate on this "trouble"? :\

[dstew]

The partitions look OK. Perhaps the boot disk got changed in BIOS. Check to see if it is booting the proper disk. It seems that the smaller, 122.9 GB disk is the one to boot.

I think grub will work without sudo on the Live CD, since you are root, but try it anyway.

[meierfra.]

since you are root

No, one is logged in as "ubuntu", not as "root":


ubuntu@ubuntu:~$

The "sudo" is necessary.

[starfailure]

Well, that was it...

I did :-$sudo grub, followed dstew's directions to reset GRUB and all is normal.
Stupid Microsoft.

Thanks for all your help.