Hi all,
I have a dual boot system - WinXP and Fedora 10.
I am happy with my fedora 10, but as usual the WinXP has lots of malware on it. So I wish to reinstall it and patch it up with a AV.
Is it possible to reinstall WinXP without breaking the system - becoz AFAIK, installing will remove grub from the superblock and then there will be no way to reload fedora even if it is still there .
Can't I copy grub and the partition table away and reinstall it from windows after the intallation completes ?
That way I shall have my dual boot system back as usual if I didnot do any changes to the partition table during the fresh windows installation.
Am I right ? If so then can someone give me the steps to do just that ?
thanks in advance
nishith

After reinstalling xp, you should be able to use your fedora install disk to repair/restore the grub. If you're not using xp for gaming, it might be more convenient to install in into a virtual machine, like VirtualBox or VMware.

You mean - just insert the installation DVD and choose the option in the main menu to repair an existing install?
BTW, I have not created any recovery disk or anything like that !
nishith

Yes, that's what I mean.

There are plenty of threads on this board covering it. I would suggest you search them out and familiarise yourself with the technique before proceeding.

It would also be prudent to backup any important data. Re-installing xp shouldn't have any effect on your fedora install, however there are no guarantees!!

Good Luck.

You can, of course, use any "live" CD to boot from.

Richard

Here's how to back up your boot sector and partition table
first, in case the Windows install does nasty things:

dd if=/dev/sda of=/tmp/thankgoodness count=512

Then save the resulting file, /tmp/thankgoodness, to some
removable media such as a USB drive. Make sure you tell
tell Windows where to install and don't let it partition
your drive. Google "install grub" and print out the
instructions before installing Windows. Basically you'll
boot from your Linux installation CD, go into rescue mode,
the run grub-install to put grub in the boot sector.

I'll repeat what {BBI}Nexus{BBI} said, too - if you don't
use Windows a lot, it can be more convenient and safer
to run it virtually, inside of Linux. Particularly if
you have a recent processor with virtualization support,
qemu and Xen and free virtualization systems for running
other operating systems inside of Linux. Xen can only
run Windows if your processor has the needed VT support,
while qemu can run it on any processor, but one without
VT support will be slow.

Even with VT support in the processor, virtualization
of Windows hurts performance because it doesn't know
how to be a good guest within another system. So if
you use Windows a lot, the easier softer way is a second
hard drive. That avoids worries about the Windows
installation messing up Linux, so long as you make sure
to install Windows on the correct drive. Unplugging the
Linux drive while installing Windows would make it safer,
but then one system would be confused when the drive
letters changed after you plugged it back in. You'd
need to switch Linux to boot from /dev/sdb rather than
/dev/sda, or else switch Windows to boot from the second
drive somehow, so I'd leave both drives plugged in.

I made it work by installing windows on a separate drive. I disconnected power from the linux drive. Installed windows, reconnected the linux drive and ran an update of the linux OS. The linux OS was Mandriva 2009 by the way. An excellent distribution.

yes it is always possible to reinstall windows xp on your system which has fedora installed on it u just need to update the grub after installation of xp . Insert the fedora cd and choose update system then it will ask if u wish to install grub or not. choose yes to install the grub.the system will automatically update the grub

I have done it myself several times and I assure you it really works....

What about a Super Grub Disk?

It's an easy way to repair a damaged GRUB.

http://www.supergrubdisk.org/

=)

thanks for the overwhelming support...
I got it right.
thanks again
nishith

Hi,

My post is probably delayed. I would like to share a solution to the multiple boot dilemma. It was posted online somewhere, but I forget the source now.

The trick is to install Linux with the boot loader on the root partition rather than on the MBR. Fedora/Redhat and many others give this option. For example, let us say that your Fedora is installed on /dev/sda5 (/). Then you should opt for the bootloader to be installed on /dev/sda5 rather than on /dev/sda.

On reboot after installation, Fedora will still not be bootable yet, so we run the install DVD in rescue mode. We need to write to a destination that can be read on Windows. Typically, this turns out to be a USB flash disk. If you have a FAT32 partition on the hard disk, even that will do.

Determine your flash disk device name by running
#fdisk -l

at the rescue prompt. I am assuming that it lists /dev/sdc as the device and /dev/sdc1 as the FAT partition on it.

Mount it with the following commands
#mkdir -p /tmp/mnt/flashdisk
#mount -t vfat /dev/sdc1 /tmp/mnt/flashdisk

Save the boot information on Fedora's root partition to the flash disk
#dd if=/dev/sda5 /tmp/mnt/flashdisk/fedora.lnx bs=512 count=1

Next, we reboot and allow Windows XP to boot up. Copy fedora.lnx file from flash disk to the installation drive of Windows (just a suggestion). I am assuming this is C:\.

Open Control Panel. Double-click on System. Click on Advanced. Under Startup and Recovery, click Settings. Under System Startup, click on Edit button. A notepad window with boot.ini opens up. Under [operating systems], add a line under the existing line
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft ...

like so:
C:\fedora.lnx="Fedora"

Now, your computer should boot using Windows, but give an option to boot Fedora as well. It has worked fine for me. Repeat the steps as and when you install Fedora or Windows, and you don't even need to rerun GRUB.

I don't have Windows XP Home, so I am not aware if procedure changes in any way.

nandanlbhat,
you get the bootloader of grub or of windows ( the black one ) after you set up the system the way you suggested ?
nishith

Hi Nishith,

The first screen is of Windows bootloader. If you select Fedora from this selection, the control jumps to GRUB.

In fact, if you are aware of multi-booting Windows and Linux, then you probably know about the GRUB entry for loading Windows. This entry will still work in the new setup. However, it results in jumping back to Windows/Fedora boot screen of the Windows bootloader.

In my setup, I have the Windows/Linux selection managed by Windows bootloader. All Linux boot entries are in GRUB. That is my preference. You could have all of those entries in Windows' boot.ini itself.

(Removed the portion about ntfs-3g, since Rescue mode does not seem to have ntfs or ntfs-3g in Fedora 10 i386)

Cheers,

Nandan

thanks once again for the support. And thanks to Nandan for giving the new option - which I wish to try out on newer installs.
BTW I realised after I started off reinstallation of winXP on the dual boot system, that the winXP CD halts while detecting the hardware during the setup process. It just won't proceed. Nothing wrong with the CD as it works fine on other machines. Also this has been reported by others on the net but no satisfactory solution was evident from those posts. So here is my setup :-
I have only one hdd on my laptop /dev/sda
I have winXP on sda1 and fedora on an extended partition sda5
I have grub loaded on sda i.e it displaced MBR.
I wish to reinstall winXP and later on get the dual boot system running - by backing up my grub and reinstalling it or by doing a reinstall of the grub from the rescue mode of installation DVD.

Is it possible to do the above ?
thanks in advance
nishith

Hi nkd,

I am guessing this forum would not be appropriate to figure out why a Windows XP install stalls midway. I hope it resolves for you. My suggestion is to try removing any hardware or supply driver disk via floppy (F6) method to work with some of the newer hardware.

Backup all the data that you wish to retain after the installation process - from Windows and Linux. One wrong step will have you in a panic if you don't backup data. Utilities like SystemRescueCD can help you backup data without requiring to boot the system on sda (provided there is no disk failure).

There is no problem with having only 1 hard disk for multi booting Windows and Linux. Windows set-up will prompt you for partitioning. It needs to know only about the partition where Windows will be set-up. It will not bother itself with unknown partitions (Linux), unless you choose to delete those partitions.

A Windows install will rewrite the MBR to use Windows bootloader. Use raymor's suggestion to backup GRUB if you intend GRUB to eventually be put on MBR. Use my procedure if you don't want to disturb Windows.

Nandan