Ok so for a long time I had my dual boot working great, windows and ubuntu. But 2 days ago my windows required a wipe and clean install because of some issues, like it usually happens after 8 months.

So I reinstalled windows, well, first deleted the windows partition using the windows XP install CD. Then assigned a partition for windows (same size) and left the ubuntu and swap partition intact. But of course, windows deletes GRUB and replace it with their boot info, so now I can't boot ubuntu (I can't choose).

How can I reinstall GRUB without having to reinstall ubuntu, so I don't lose all my files and settings?

I had to deal with similar issue (reinstalling Windows XP with Ubuntu 7.10 already installed), except I didn't delete the Windows partition, just formated. The thing is, at least according to my limited "boot" knowledge, that you have probably made the old GRUB unusable, since the Windows practically isn't on the same partition any more. This, however, shouldn't prevent you from trying the method I used. Be aware that I have done this only once, so there is a slight risk when following my instructions.

First of all, insert the Ubuntu Live CD and boot the computer from it. After doing so, and starting Ubuntu, run the Terminal (Applications -> Accessories -> Terminal) and run the following commands.



After doing so, you will start the GRUB configuration utility which will allow you to setup GRUB on a desired partition.



This command will output (hd*,*), the asterisks being some numbers. Now you need to run these commands (replacing the asterisks with the numbers you got):



Exit Ubuntu, remove the disk and reboot your computer. You should now get the GRUB bootloader.

The chances are Ubuntu will run properly, but due to the deletion of a partition, Windows might not. If that is the case, start Ubuntu and run this command in the terminal:



The file menu.lst should contain something like this:



If Windows doesn't boot, the root line is wrong, and you need to replace (hd0,0) with the proper partition. Which one and how to do so? That I don't know...

Pyost's instructions are correct. That's in the case where you lost your GRUB menu during startup.

I am Quin-Booting or should we call it Penta-Booting (5) different Operating Systems in my AMD Machine, I experience a lot of times 'losing' my OSes when scrumbling more OS in a single PC, single hard drive.

This post has been edited by rockershive: Apr 1 2008, 02:04 AM

Instead of the common grub-based dualboot setup, you could use a program called HyperOS. It has had support for linux since version 2004 I believe, however I think it costs money.

thank you pyost, it worked like a charm! sorry for taking too long to respond, but I didn't have time to try it. I did it and it works!

woot =D

error in finding grub
Ubuntu 7.10 + Windows Xp Dual Boot

I ran the sudo grub command. Ok
Grub> find /boot/grub/stage1 says file not found.
Pl. Advice

-question by syed

We have already installed UBUNTU but when I am trying to get in it's showing Disc Error. What should I do?