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Windows 7: Untangle my XP and Win7 Dualboot

29 Nov 2012   #1

Windows 7 Professional 32bit
Untangle my XP and Win7 Dualboot

Hey, guys. I'd love some experienced advice! First, just to prove gray hair doesn't mean wisdom:
I've almost always (well, since 1998) run dual-boot systems: I went from Windows 3.1.1 to a Win 95/Win98 dualboot using Bootmagic. From about 2001 I used WinXP Pro/WinXP Pro (one for audio editing, one for business), then WinXP/Win7 in October 2009.
I've built my own PCs since 1998, so far without a failure; I've also done two (Cert III and IV) courses in Hardware, Software and Networking . . .
So I'm embarassed to admit to TOTAL ignorance when it comes to untangling a dualboot!
My current setup is WinXP Pro (Games, installed first), then Win 7 Pro on a separate drive, using EasyBCD for my boot menu. Both these volumes are Active Primaries. I have just added XP Pro (audio editing) and GAG boot manager on an OCZ SSD, but this operating system is distinct and separate from the others, so I won't discuss it here.
I want to individually launch my OSs as required, using GAG. I THINK that will mean rebuilding the boot sectors in each of my first two OSs so they each have their own valid Partition Boot Record; then replacing the ntldr and boot.ini files (into the XP volume), and bootmgr and BCD files (into the 7 volume). I assume their MBRs are undamaged. Has anyone done this? I want to use bootrec.exe (or bootsect) for these repairs (?), but my confidence seems to have deserted me! I have attached (i) the original XP partition (you can see the imposed Win7 boot manager), and (ii) my Disk Management view.
Untangle my XP and Win7 Dualboot-games-volume.jpg
Untangle my XP and Win7 Dualboot-disk-management.jpg
Any ideas? I'd kill for some help!

My System SpecsSystem Spec
29 Nov 2012   #2

Win 8 RP, Win 7, XP

Hi RumJungleMusic,

The boot sequence from hard disk for every Windows system (XP, Vista and later) is the same:
1. MBR (first disk)
2. PBR on active (first disk)
3. OS loader/boot manager (ntldr / bootmgr) again on active (first disk)
[boot.ini eqivalent in Win7 is \Boot\BCD file]

MBR code can be NT5(XP) or NT6(Vista and later) - does not matter.

PBR code must correspond to OS - for XP -> NT5, for Win7 -> NT6
bootsect.exe has switches /nt52(XP) and /nt60(Vista and later)

No need to fix ntldr - it is already there, only boot.ini should be checked for correctness.

For fixing Win 7 boot files you can use bcdboot.exe.
(for example "bcdboot c:\windows" is all that is needed)

Best is you make every disk bootable and check if everything is OK when other disks are disconnected.

What you need - a Windows 7 Recovery CD (can be created in Win7).
On the recovery CD you have:
bootsect.exe (fix for MBR and PBR)
bcdboot for fixing bootmgr, BCD and other boot related files.

You can prepare boot.ini by putting default ARC path (multi(0)disk(0)rdisk(0)partition(1)\WINDOWS) for default and OS:

[boot loader]
[operating systems]
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Windows XP" /fastdetect
assuming that partition1 (first primary partition is active).

Later when all disks are put back in the system things will change !

Eventually boot.ini and BCD have to be adjusted again.
All "boot addresses" as you can see in boot.ini (ARC path) are "absolute":
first is disk position (0,1,2,....) then partition(1,2,3,....)
please note disk numbering starts from 0, partition numbering from 1 !

Note 1 (be prepared for the worst case):
You can always fix Windows 7 booting using the recovery CD and "StartUp Repair" option. Windows 7 must be the only disk attached when fixing for best result.
Sometimes you have to run StartUp Repair up to 3 times with rebooting after each run to achieve fixing.

Note 2:
For XP only boot.ini has to be adjusted for correct booting.
In your case only rdisk parameter has to be eventually fixed !

You can use ArcPaths utility to display ARC Path to drive mapping.

In BCD the "boot addresses" (device parameter and osdrive parameter) are in the form "\Device\HarddiskVolumeN" (this is usually mapped to a drive letter like c:, d:, ...) where N is a number starting from 1.
You can use the utility WinObj from SysInternals to view drive to volume mapping.

I suggest before starting changes and fixings you get used (if you are not already) to all utilites (bootsect, bcdboot, WinObj).
For editing BCD you can use bcdedit or Visual BCD Editor.

Hope this helps.
My System SpecsSystem Spec
29 Nov 2012   #3
Microsoft MVP


To use the automated method which checks all parameters including assuring System Recovery Options
are linked to F8 Advanced Boot Options:

Unplug all other HD's but Win7 HD, reboot into BIOS setup to make sure Win7 HD is set first to boot (after DVD drive), boot into Win7 DVD or System Repair Disk to run Startup Repair - Run up to 3 Separate Times until C holds the System Active Boot flags and boots on its own.

When you plug the XP HD back in, boot it via the one-time BIOS Boot menu key given on first screen. If this is not to your liking, install EasyBCD to Win7 to add XP which will keep both HD's independently bootable.
My System SpecsSystem Spec

29 Nov 2012   #4

Win 8 RP, Win 7, XP

XP is first disk in BIOS in current setup as can be seen in posted screenshot.

XP disk has to be fixed also as goal is to separate XP and Win 7 completely.

GAG will be in control later for booting XP and Win 7 as posted by OP.
My System SpecsSystem Spec
29 Nov 2012   #5
Microsoft MVP


I'm assuming XP Games is the XP OS partition since it's marked System Active as it would be if 7 were installed last while XP was still plugged in.

So yes it would be set to boot first since it is booting both OS's, which is why I said to make sure Win7 is set to boot first in BIOS after unplugging XP so it won't interfere. Then Startup Repair when run up to 3 separate times will write the System boot files to C, and check all parameters beyond just the boot function.
My System SpecsSystem Spec
29 Nov 2012   #6

Windows 7 Professional 32bit

Thanks guys - I'm considering my options! I will probably go with the more 'hands-on' approach - great detail, thanks boyans. The boot sequence is just as I expected, but it's good to know that NTLDR is probably OK. I will use my boot.BAK file, renamed to its original boot.ini. It still contains a valid ARC path: {multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP Professional" /noexecute=optin /fastdetect}. I'll perform each repair with the other disks disconnected, and just remove the 'superimposed' bootmgr file from the root of XP (Games). GAG will hide other active partitions on boot.
Waddya think?
Also, considering each OS is on a separate HDD, do they all require an MBR in the first sector (or does a bootmanager such as GAG directly address the PBR of each system volume)? I have GAG already installed in the MBR sector of my newest OS, XP Pro (Audio Workshop), and my BIOS defaults to this drive. I really appreciate the information I've already been given - thanks to both of you!
My System SpecsSystem Spec
07 Dec 2012   #7

Windows 7 Professional 32bit

I've got each OS booting separately using the BIOS; however, I'm afraid that with all drives reattached, XP could tank my Win7 Sys restore. Or worse. Do you know if booting from GAG will circumvent this problem?
My System SpecsSystem Spec
07 Dec 2012   #8
Microsoft MVP


You'll have the least problems booting from BIOS so that they OS's are independent. Why would they become more independent by installing a program on one to dual boot both?
My System SpecsSystem Spec
10 Dec 2012   #9

Windows 7 Professional 32bit

Sorry, Gregrocker, I hadn't meant to give that impression. I would install GAG not to ensure independance, but to make OS selection convenient, without having to boot into the BIOS.
I will be accessing 4 OSs (XP x 2, Win7 32-bit & Win7 64-bit), and when set up, GAG (I imagine) would give an easy, descriptive list to chose from.
Thanks again for your time & experience - very much appreciated.
My System SpecsSystem Spec
10 Dec 2012   #10
Microsoft MVP


In the past when having a Windows Boot Menu is important we have found EasyBCD Download Registration - NeoSmart Technologies does the job best to add the other OS's from Win7.

Please let us know how GAG works for you.
My System SpecsSystem Spec

 Untangle my XP and Win7 Dualboot

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