Dual Boot DOS & XP Pro

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G

Guest

Hello.

I had a PC set up to dual boot DOS & XP Pro. The DOS partition was formatted
as FAT16 and located at the front of the drive and set active. The XP
partition was NTFS formatted and occupied the rest of the drive. Both of the
partitions were primary. Unfortunatley when the PC arrived at it's
destination someone reformatted the FAT16 partition and reinstalled DOS. Now
the PC boots directly into DOS. How do I repair the dual boot without having
to reinstall XP. I have a test PC set up like the other PC but running FIXMBR
from the recovery console did not work. Thanks for any help you can provide.
 
rgw said:
Hello.

I had a PC set up to dual boot DOS & XP Pro. The DOS partition was
formatted
as FAT16 and located at the front of the drive and set active. The
XP
partition was NTFS formatted and occupied the rest of the drive.
Both of the
partitions were primary. Unfortunatley when the PC arrived at it's
destination someone reformatted the FAT16 partition and reinstalled
DOS. Now
the PC boots directly into DOS. How do I repair the dual boot
without having
to reinstall XP. I have a test PC set up like the other PC but
running FIXMBR
from the recovery console did not work. Thanks for any help you can
provide.
Click to expand...


Microsoft's "dual-boot" (although more than just one OS can be listed
in boot.ini) is a bastardization of a boot manager. Many boot
managers run by themself without an OS (i.e., they let the BIOS load
the boot manager and pass control to it). Microsoft has you first
load their NT kernel (loader) that then reads their boot.ini to then
load that OS; i.e., you load an OS before you get to choose which OS
to load.

FIXMBR only replaces the 446-byte boot code area in the MBR (master
boot record = 1 sector in 1st track on 1st hard drive discovered by
the system BIOS). All the std boot loader does is check the partition
table in the MBR to see which is currently marked as the "active"
primary partition. It then uses those offsets to find the start of
that partition and loads whatever is in the boot sector of that
partition, like the loader for the OS. So running FIXMBR won't change
which is the active primary partition.

You could try using FDISK to make the NTFS partition the active one
and hope that it loads okay (to then read boot.ini to present you with
choices of OSes). Or you could forsake the std boot loader in the MBR
and use a boot manager there, like GAG (gag.sourceforge.net). You can
run GAG from a bootable floppy until you are ready to copy the
customized copy into the MBR's bootstrap area. Having configured it
on floppy means you can also have it available in case, as you found
out, someone steps atop the MBR bootstrap area so you can put GAG back
on just the way you wanted before.
 
There are several things that you need to do to restore the NT boot
loader and to regain dual boot capabilities:

1- Copy the files NT (XP) files boot.ini, ntldr, NTDETECT.COM to the
root of the FAT16 partition. The file boot.ini is created when Windows
is installed, you will have to recreate it, it can be recreated manually
or you can boot to the Recovery Console and use the BOOTCFG command to
recreate it. You can copy (extract) the other files from the XP CD to
the root of the FAT16 partition.

2- You will have to boot to the DOS installation and use the ancient
DEBUG command to create a bootsect.dos file for the DOS installation.
This file is needed by ntldr to boot DOS.

3- You will have to boot to the Recovery Console and issue the FIXBOOT
command on the FAT16 partition then issue the FIXMBR command.

Another way of doing all the above in one fell swoop is to install the
Recovery Console, that should do everything that is needed to restore
the boot loader to ntldr and at the same time it should create the
boot.ini and bootsect.dos files. You can create a floppy boot diskette
to access the Windows XP installation and then proceed to install the
Command Console, that should do the trick. Note that to create an XP
floppy startup diskette you *must* format the diskette with an NT
machine, you cannot format it with a DOS?Win9X machine, if you do the
diskette will fail to boot the XP installation.


How to install the Windows Recovery Console
http://support.microsoft.com/kb/216417

How to create a Windows NT 4.0, 2000, XP or Server 2003 boot floppy disk
http://www.nu2.nu/bootdisk/ntboot/

How To Create a Boot Disk for an NTFS or FAT Partition in Windows XP
http://support.microsoft.com/kb/305595

John
 
rgw said:
Hello.

I had a PC set up to dual boot DOS & XP Pro. The DOS partition was formatted
as FAT16 and located at the front of the drive and set active. The XP
partition was NTFS formatted and occupied the rest of the drive. Both of the
partitions were primary. Unfortunatley when the PC arrived at it's
destination someone reformatted the FAT16 partition and reinstalled DOS. Now
the PC boots directly into DOS. How do I repair the dual boot without having
to reinstall XP. I have a test PC set up like the other PC but running FIXMBR
from the recovery console did not work. Thanks for any help you can
Click to expand...
provide.


from the recovery console try the command fixboot
 
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