messed up MBR

[starvingartist]

Setup:
One laptop with unpartitioned HDD, one Xubuntu 8.04 on a USB drive.

Problem:
GRUB doesn't work for XP. The only option I get when booting is Xubuntu. Great OS, but I need XP for work tomorrow.

My HDD isn't recognised at all when I use Super Grub Disk. Gparted does recognise it in Xubuntu, but shows a warning sign (doesn't explain it, unfortunately).

Any attempt at reinstalling the MBR (syslinux) through Super Grub Disk have failed. When trying to access XP the only output is:
makeactive
chainloader +1
boot
GRUB

... and that's it. As this is a company laptop, I do not have the XP disc. I would love to be able to try 'fdisk /mbr' or NTLDR somehow. Any help is greatly appreciated.

And yes, I know I shouldn't have done this without adequate recovery gear handy.

[nick_h]

You can restore a Windows MBR using the ms-sys package. Have a look at the following howto - HOW TO: Recover Windows MBR using Ubuntu LIVE CD

[starvingartist]

hmmm... even with all software sources open it cannot find the file ms-sys.

[d-mart]

I always use the super grub live cd when I have any grub issues

Sorry didn't read post carefully enough

however i did have this problem before and i believe i fixed by following this

http://mandrivausers.org/lofiversion...hp/t46674.html

[starvingartist]

I always use the super grub live cd when I have any grub issues

I seem to have used that CD to break my MBR, or more specifically: I removed the MBR completely from hd0. However, for some reason it won't reinstall.

[d-mart]

the only thing i could think of off the top of my head to fix it is to remove the usb and run supergrub just trying to just get windows to boot by using the options on supergrub if you can get that done then you just need to change your bios to boot from the usb before your hdd and install grub on your usb so it only uses grub when the usb is inserted.

Sorry if this doesn't help but its all i can think of right now and i have to leave in a sec.

ps here are two more links that discribe using "zero fill" to fix your boot of xp
http://www.codeproject.com/KB/work/i...91#xx1764691xx

http://ubuntuforums.org/archive/index.php/t-593740.html

however i would be real carefull using "zero fill" sounds sketchy to me

[starvingartist]

SGD doesn't help at this moment, my mistake was obviously major. Apparently I removed all the boot info from the XP drive.

One thing I was thinking (long shot): if I want to run fixmbr, could I install XP Home on my thumb drive, then boot from that and fix the MBR of the original XP corp from there?

Getting desperate here... does it show?

[nicedude]

You could use an Ubuntu Live disk to boot to a working environment and then run grub and have it reinstall its self to your MBR. If I read your description of your problem correctly then you have XP on your laptop hard drive and you have installed Xubuntu to a USB stick if that is the case then when you installed Xubuntu grub rewrote your laptop hdd mbr and that is where your trouble lies. Your usb drive should have a directory /boot/grub/ on its root that will contain your Grub menu.lst which is the list of available systems to list at boot time if you edit that file correctly you should be able to boot to XP again. Also there is a way to use advanced grub commands at boot and thereby call the chainloader but I don't know them off the top of my head so maybe someone here can chime in with that info.

You could also get a bootdisk from http://www.bootdisk.com/ for XP that might let you fix MBR if my other advice is unworkable

Sorry to hear you goofed up your work PC hope you get it fixed before work

If I am wrong about your predicament sorry.

[starvingartist]

You could use an Ubuntu Live disk to boot to a working environment and then run grub and have it reinstall its self to your MBR.

Well, Xubuntu is working fine. That's what I'm using right now. IT's just that the HDD with XP isn't recognised at all any more -- not even by Super Grub Disk. However, when checking with gparted I can see that it still exists.

If I read your description of your problem correctly then you have XP on your laptop hard drive and you have installed Xubuntu to a USB

Precisely.

if that is the case then when you installed Xubuntu grub rewrote your laptop hdd mbr and that is where your trouble lies. Your usb drive should have a directory /boot/grub/ on its root that will contain your Grub menu.lst which is the list of available systems to list at boot time if you edit that file correctly you should be able to boot to XP again.

I'd be happy to if I knew how. The current situation: the GRUB menu loads fine for Xubuntu, but doesn't display XP at all. Booting XP directly from SGD doesn't work, reinstalling the MBR with SGD doesn't work. It seems I have manually removed something (?) which was critical.

Also there is a way to use advanced grub commands at boot and thereby call the chainloader but I don't know them off the top of my head so maybe someone here can chime in with that info.

That's about the time where I messed it up. After the chain loader thingy was done, neither OS would start. Had to reinstall Xubuntu completely to get that functioning on my USB again.

You could also get a bootdisk from http://www.bootdisk.com/ for XP that might let you fix MBR if my other advice is unworkable

Interesting, will look into that right away!

Sorry to hear you goofed up your work PC hope you get it fixed before work

My fault for not leaving well enough alone. Thanks for the input!

[nicedude]

OK starving artist here is some advice for if your

Reboot the pc and press escape to see the grub menu if it is not displaying , then press "c" to get a grub command prompt

NOW TYPE THESE COMMANDS ONE AT A TIME
rootnoverify (hd0,0)
makeactive
chainloader +1
boot

Enjoy XP as that should work assuming XP is installed on your laptops first partition. Please report your results.