What is the way to modify the boot sector of a Hard disk ?

Like suppose I install Windows XP on my computer, it makes the hard disk bootable by modifying its disk space. Now, suppose I decide to install Linux on my computer too and have a dual boot of Windows XP and Linux. (Please note that the Linux I am using is Ubuntu 5.04i). Since Ubuntu requires partitioning of harddisk, I decide to install it on a separate hard disk. During installation, it says to install GRUB BOOT LOADER to my first harddisk or gives option to install to a floppy. I decide to install on my first hard disk. Now, my computer is bootable only if my ubuntu harddisk is connected, and I cannot boot from my main hard disk if I remove my ubuntu harddisk. Now what to do in such a situation? Say suppose, my ubuntu harddisk was old and now it has crashed, how can I make my computer bootable back to Windows XP again? I think installing Windows XP again from its CD will do the job but I am not sure. And what to do if I cannot reinstall Windows XP or if I don't have its CD?

I have Windows 98 CD and by it I can manage to go in DOS. Is there any software or tool or tricks available for this problem of booting? Is there any way to modify or rollback the boot sector of my first harddisk?

configuring boot.ini leads to hell=)
at least i dont know of any like that, i would reformat and reinstall everything and have ONLY ONE HDD connected while installing operation system. if you install linux- it always messes up boot sector(at least for me it does).
then its not problem to just boot from another hdd from bios is it? ;)

To change MBR (Master Boot Record), you will have to rewrite it. To do this, you can use fdisk that comes on your Win98 CD. Just type at the dos screen. Be aware that this might lead to problems, if you don't know what are you doing.

I did this more then once, and it helped me to avoid reinstalling of a good system.

But first of all, read more about it. Here are some links:

http://support.microsoft.com/kb/q69013/

http://www.computerhope.com/issues/ch000175.htm

http://www.fdisk.com/fdisk/

http://www.pcguide.com/ref/hdd/file/progFDISK-c.html

Good luck! :bye:

Windows XP + ubuntu Linux

(This will only work with the retail version of XP)
:Install XP:
Make two partitions, one for windows XP, and one for file transfer, leave space for Linux.

(example: 160GB HDD: 100GB Windows XP [NTFS], 10GB [FAT32], 50GB Linux [EXT3])
For the FAT32 partition use partition magic.

Once XP is installed we can go on to the Linux install.

:installing ubuntu:
Once you get to the partition editer select manualy edit partition table.
Make a EXT3 partition to install ubuntu on and set as active.
When it asks if it wants to install the GRUB boot loader select yes.
Finish the install.

:)

Using fdisk usually lead to a whole format of the drive, so I would be very cautious if I'm you if you want to go that way.