Windows XP and Windows 7 dual boot problem


New Member
I was running windows xp on my machine, I installed the beta of Windows 7 and put it on a seperate partition by using the advanced set up option in Windows 7 installation.

After that Windows 7 started up fine, but XP was missing as a boot option. I discovered that in Windows 7 my XP partition had been renamed from C: to D:.

I used EasyBCD to add the XP install as a boot option and copied over the 3 boot files from the XP partition to some unnamed partiion which I called L, I then set the following

Entry #1
Name: Microsoft XP
BCD ID: {19036fc2-f358-11dd-8b00-94391b5f3846}
Drive: L:\
Bootloader Path: \NTLDR
Entry #2
Name: Windows 7
BCD ID: {current}
Drive: C:\
Bootloader Path: \Windows\system32\winload.exe
Windows Directory: \Windows

I also had to change the rdisk values from 0 to 1 in the boot.ini file on the L drive

In computer management the drives are listed as follows

disk0: D: Active, Primary partition (My Xp drive), C:Boot, Page file, etc, E: Logical Drive
disk1: L: System, Active, Primary partition

Once I did all this I was once again able to boot into the XP install, but now it acts funny. It shows itself as being C: in the XP install itself and the drive letter assignments are all different from Windows 7 , but it wont run any programs installed on C:

Does anyone know what I should do to fix the XP install?


Knows where his towel is.
Staff member
That fix from Guru, is for if XP when it's booted, thinks that it's not the same letter as it used to be (C:\ presumably).
The fact that W7 calls it D is of no importance.
Disk letters are purely internal to the running system. There is no physical letter attached to the hardware.
My Vista is C: and it calls W7 I:
If I boot W7, it calls itself C: and it calls Vista I:
That's perfectly normal.

If the software on XP that won't run any more, put some of its files or data on another partition which has changed its letter (in XP's mind), you'll need to use disk management to shuffle the letters till XP sees the partitions it's used to, with the same letter assignments as they had previously.
This might be a problem if the W7 partition currently uses the letter, because disk management might not allow it to be renamed if it contains some of the restricted flags (page, system etc).
If none of those flags show on W7, when seen from XP, you should be fine.
If disk management won't allow the rename, you can zap the W7 letter in the registry.
The link Guru gave will show you where in the registry, but in this case it's the W7 partition, not XP itself that you'll need to alter.
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Mostly Harmless
Staff member
I thought he meant that was from within XP.... my apologies.


New Member
Sorry guys, I know my explnation was somewhat confusing. Everything in XP appears to be assigned the drive letter it had before. I can't even load Disk Management in XP though, it tells me something about it failed to load it. I can get the exact message, but currently I'm about to leave for class.


Knows where his towel is.
Staff member
I'm puzzled by this "some unnamed partition" you've put the boot files in
It's a "system" "active" drive so that's where W7 would have put its BCD.
Is it first in the BIOS boot sequence ?
Is there any chance you've got an old XP install on there ?
Was it on the system before you installed W7 ?
What was it used for ?


New Member
Windows 7 created it when I installed it. It made some new 200 mb partition and filled like 198 mbs of it. It also didn't assign a drive letter to it. I had to assign one so that I could open it and put the boot files in it. I then had to point XP at this partition to get it to load.

In windows 7 disk management is says that this partition is on disk1 and has the following flags

disk1: L: System, Active, Primary partition

I'm not sure what it is, and it is not visable when i boot windows xp, Windows 7 is installed on what is it calling C:

which has the following flags C:Boot, Page file, etc. I think when I tried to point XP to this drive it would tell me hal.dll was corrupt, and would not boot XP.


Mostly Harmless
Staff member
Terry, if during Windows 7 setup you install it to an un-partitioned disk, it'll automatically create *two* partitions - a 200mb letter-less partition as system/boot for bootmgr & bcd, and a huge partition for 7.

That unnamed partition is what makes EasyBCD prompt users to pick the _letter_ of the boot drive when running on 7 many times.

dgg04, I don't understand.

Please verify:
1) You *are* able to get into XP, correct?
2) But XP isn't working properly, though you get into it, it's acting up?


Super Moderator
Staff member
Windows 7 creates two partitions automatically in case the user wants to set up bitlocker drive encryption later on down the line so the files needed to boot the computer are already seperate of the system partition bitlocker will encrypt.
Yes, after putting the boot files into the unnamed partition and changing boot.ini rdisk settings from 0 to 1, I was able to boot into XP.

When I boot into XP, however, it is messed up. For example I can't load disk management, and when I click on a program that is installed on the XP partition it will not load.

However, some programs installed on a seprate storage partition still run okay.

edit: Also I just wanted to add that for some reason it decided to make the smaller unnamed partition on drive 1, which is my 1 TB drive, where as the XP install, and Windows 7 install are on my 500 GB drive
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Mostly Harmless
Staff member
And does XP call itself the same drive letter it always did?