dual boot system - editing registry of 2nd OS from within 1st OS

Posted on 2006-05-21
Last Modified: 2008-03-10
i have a dual boot system here, with windows 2000 on the first partition, and XP on the second partition.

what i need is some way of editing the registry of the XP system, from within the 2000 system. after a drive failure and some recovery procedures, the XP system will not boot any more, and all my research i have done points me to a simple registry edit - but one i cannot perform as the system will not boot, not even in safe mode.

here's the long story :-

the hard drive was damaged beyond repair, and i've imaged everything to a new drive. however, the dual-boot system being used isn't the standard NTLDR boot menu, with XP bootstrapped to 2000, instead it's using the software BootMagic

for anyone who doesn't know - BootMagic used to be quite a useful piece of software back when windows 98 was a popular OS, as it allows for many combinations of multi-booting OSs, something 98 was not normally capable of by itself. BootMagic is largely redundant these days as XP (and indeed, any NT based OS) can multi-boot all by itself

the way it works is by playing with the MBR of the drive, to hide partitions - so that if you boot to the first partition, the 2nd partition is hidden from the OS - and vice versa. a bit messy, but it works.

unfortunately, at some point during the recovery process, something has happened with the drive letters, and the 2nd partition (XP) has been set with an incorrect drive letter, and nothing i have tried can fix it. the result of this, is that XP will not boot, not even in safe mode - it gets to the welcome screen, then hangs (which is a symptom of the system's drive letter being changed, i've seen it before)

the only way i can access this drive is from the first OS (2000), from where i can either set the drive to be D: (correct from 2000, but incorrect for XP, it has to be C:), or i can remove the letter association altogether. of course, this is also the same if i install the drive to another system, i am unable to actually set the partition to be drive C: which i believe is what it wants - removing the drive letter association hasn't caused it to become reset to C: when booting the drive, and setting any other letter also has not solved the problem

according to the microsoft knowledge base article 223188 - - it's possible to change drive letter associations within the registry, in order to restore a volume that will not boot. however this article strangely assumes that you can boot to the volume that does not boot - because how else can you make the registry changes !

so, the bottom line is - i need to boot to 2000, then from there somehow edit the registry of the XP system. i'm not confident that it's possible, but it seems to be the last option i have before reinstalling XP (and correctly bootstrapping it to 2000 if i do have to do this). of course, any other suggestions that solve the problem will also be welcome.

i will not be awarding points for suggestions to format/reinstall the OS - this is something that's already been considered, and i'm trying to avoid - points will only be awarded to suggestions that enable the existing OS to boot again.

thanks in advance

Question by:Statick001
    LVL 95

    Accepted Solution

    Forget 2000 - there is a tool on the Ultimate Boot CD for Windows that will let you modify the registry of the XP OS, but you need to boot off a BartPE CD with the Ultimate Boot CD for Windows and you can it's offline Registry editor.

    BartPE - available from:

    Then be sure to get BOTH the driver add on and the software add on from: (Overview) (direct downloads page link)
    LVL 3

    Author Comment

    oh, i've got BartPE already - never had a use for it though. i'll certainly check that out, thanks a lot !
    LVL 95

    Expert Comment

    by:Lee W, MVP
    Keep in mind, this is NOT available in BartPE - it IS available in the BartPE add-on "Ultimate Boot CD for Windows"
    LVL 3

    Author Comment

    yeh, just looking into it now - thanks for the heads-up

    this looks like it'll do exactly what i need it to - it says i can browse to the relevant hive manually, and edit that, so there should be no problem with there being 2 OSs installed

    500 points are yours

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