How to dual boot Win 7 64-bit and Win 7 32-bit

Marylin · 23 Jan 2012

I want to set up a dual boot between Win7 Home Edition Premium 64 bit and same 32 bit. The machine came with the 64 bit W7 already installed. I bought an extra W7 package. As received, the disk is set up like this : one primary 19 GB partition for restore, one primary, active partition called "system reserved", of 100 MB which contains only the set of boot files, and one primary with all the Windows files (C: ), which I have shrunk to 125 GB. Behind that, I have created an extended partition with several logical drives. At this point, this works OK.
I want to install my 32-bit Win 7 on the second logical drive (E: ), hoping it will "share" the 100 MB "system reserved" boot partition. Will there be any problem between the boot files of the 64-bit and the 32-bit versions in the same partition – they probably have the same names, may be they are the same? Would I need to enlarge the system reserved to 200 MB? Would anyone suggest a better way to add the 32-bit OS?

Maguscreed · 23 Jan 2012

It should not create a problem. Windows 7 is fairly good at managing the boot sector... and yes it should only need one for both installations. They can share the boot record. The hurdle to overcome was the second activation key. Which you have apparently already taken care of

Marylin · 23 Jan 2012

Thanks, that’s good news. Having all the boot files in a single, active, "system reserved" partition will only really make sense if this partition can be common to all the OS’s in the computer. But, once I install the additional (32-bit) Win 7, what happens with the existing 64-bit boot files in the "system reserved" partition? I guess the 64-bit bootmgr, bcd, etc files will be overwritten by the 32-bit ones (same filenames)? Can I still boot correctly my 64-bit Windows OS with the 32-bit boot files? Last question: if the 64-bit boot files have been overwritten by the 32-bit ones, will EasyBCD still find the necessary information to set up a valid link to the 64-bit Win 7?

Maguscreed · 23 Jan 2012

the 100mb reserved partition is only the boot manager really.
and it can handle multiple copies without a problem.
you could actually put vista in there too, the problem at that point would be too many partitions on the drive I would think though.

seavixen32 · 23 Jan 2012

Maguscreed is quite right - the system reserved partition will take care of the boot files.
When you've installed your second copy of Windows you'll find the boot menu on startup will show two entries both with the same name - typically Microsoft Windows 7.

This tutorial explains how to edit this information, which will help you to boot into the right OS.

Dual Boot - Change OS Name in Windows Boot Manager

gregrocker · 23 Jan 2012

To repeat: You should not need to use EasyBCD - Win7 32 bit should configure the Dual Boot Menu for you.

You did the partitioning exactly correct as far as I can tell without seeing a screenshot of your Disk management.

Marylin · 18 Feb 2012

One last question before I go ahead with the dual boot install: The first partition on my disk (even before the 100 MB "system reserved" partition) is a 19GB OEM partition which has no name and seems to be not accessible by the Windows partition manager. As far as I understand, it is there for the backup/restore system and it seems to me that Windows is automatically recording in there on a continuous basis its "current state", so, in case of a system trouble, I can "revert" to a previous, sane state. Now, what happens when I have a second instance of Windows - a 32-bit one - which might also be writing into this partition ? How can I avoid a conflict? Is there a way to inhibit "a" Windows from accessing this partition ? Thank you.

Maguscreed · 18 Feb 2012

The oem space contains a image of the computer as it was out of the box, and in some cases certain user data is backed up, it's not something I would be counting on though.

Whenever I have a physical copy of the user's windows 7 disc, I generally consider it safe to remove that partition (I usually use acronis, because as you noted, windows disk management has been specifically blocked from messing with it, though I think it's more to keep people that don't know what they are doing from wiping their own restore partition. )

The current bootmgr you are using is already accounting for this or you wouldn't be booting as it is. removing it now, may be more trouble than it's worth.... I do not see how the additional copy will cause any trouble as it will simply be added to the boot list of the currently used bootmgr.
i.e. - not a whole lot is really changing on the boot front.

seavixen32 · 18 Feb 2012

The 19GB partition will no doubt be the factory recovery partition.

If you have created a set of recovery discs (if not, I suggest you should before you go any further) then you can delete this partition. A set of recovery discs will allow you to recover your computer to its factory state should you need to do so.

If you don't want to delete it you can always go into Disk Management and hide the drive letter so that Windows can't see it.

Marylin · 27 Feb 2012

I have now attempted to install a 32-bit Win 7 as a dual boot with an existing 64-bit Win 7 the way described in the thread (custom install, on a separate partition). Unfortunately, it did not work out the way I hoped. At first, the install went very smooth and it was nearly finished when I got a window that said (my translating from French) : "The Windows Installer program has failed to setup Windows to be run on the hardware of this computer". I retried two times,
to no avail. There was no way to have a diagnosis of the problem. Could it be that the processor of my machine, a 64-bit Intel Core i7 2600 does not support a 32-bit OS ? I have looked up the specs of this chip on the Intel Website, but there is no clear-cut answer. What other reason could it be that it does not work ?
If installing a 32-bit Win 7 as second oS appears to be impossible, I shall have to install a second 64-bit one.
In this case, how can I cleanly uninstall the windows 32-bit that does not work and the two-line menu boot manager window ?