Existing 32B XP Install with 64B W7 desired

Al P

I have a 32 Bit XP installation and want to add a 64 Bit Windows 7 OS on an additional / separate drive.

Q1: Is this OK?

Q2: On installation attempt, the EasyBCD software gave error message due to me not ALREADY having W7 installed. It would appear that it CANNOT be installed on XP OS first / only, is this correct?

Q3: If I install W7 on a new drive, will the BIOS automatically give an OS BootUp option on Startup?

Q4: If answer 'NO' to Q3 above, how dto I configure / select each OS before installing BCD?

Many thanks!

1. Yes as long as your CPU supports 64 Bit.

2. Yes that is correct. EasyBCD is for use with Windows Vista/Windows 7 bootloaders, not XP's. XP does not use the BCD for booting. That was introduced after XP.

3. No. You will either have to change your BIOS boot order for the drive that you want or hit F12 to select the drive. It is not an automatic process.

4. You dont have to. You boot into Win7, add an entry for XP and then during the boot process you just select the OS of choice. you wont need to touch the BIOS or anything else after you setup EasyBCD properly.
Thanks for all your answers, now a few more questions:-

Q: Does EasyBCD appear simply as a standard application on W7, or does it's interface show onscreen before Windows BootUp?

Q: I note what you said about W7 being required for BCD installation, but will BCD be accessible from within XP thereafter also or just W7?
A. EasyBCD is just the graphical interface for editing and modifying the BCD. It does nothing more than that. If you add entries using EasyBCD, those will show up during the boot process, but nothing of EasyBCD shows up.

A. Yes you can access and modify the BCD from within XP, but as stated, the BCD is used for versions of Windows beyond XP. So really there is no need to modify or edit the BCD from another OS. If you install Win7, you should edit it in Win7. The program operates from the main OS that is boots from the MBR. So any changes made to the program afterwards have to be done with that OS in mind.

Meaning this. You boot to Win7. It sees itself as C:\ and XP as D:\ for examples. So if you are within XP and you want to make a change. You have to think this way. If you forget and dont remember that Win7 is the main drive and you make an edit, you can cause the system not to boot. It is far safer to just make the changes right within the main OS that boots to prevent such confusion.
Thanks for all your valuable comments.

Q1: Is it OK to boot from XP on C:\ with W7 on D:\?

i.e. can I leave XP on C:\ as my 'main' bootable drive, install W7 to new D:\ drive and edit / configure BCD from within the interface in XP?

Q2: If I understand you right - you recommend editing EasyBCD from within the CURRENTLY selected bootable OS (either XP or W7, in my case) - is that correct?

( I think I might be confusing myself now! )
Last edited:
Disconnect the XP drive while you install W7 to the new drive to force W7 to install its boot files on the same drive as the OS. (By default, if it sees XP as "system" it will add the boot files to the old OS drive).
Reconnect XP when the W7 install is finished, and from W7 add an XP entry (auto) to the BCD.
Any housekeeping you subsequently wish to do to the BCD can be done from either system.
Both will be C: whilst booted, but be given a different letter when the other system is booted. (disk letters aren't real, just registry entries in the running OS)
There are no disk letters in the BCD (remember they're not real), so what you see in EasyBCD is a translation of the unintelligible UID info into the letter as seen by the running system. If you ever need to specify a letter, remember to use the one that the system running EasyBCD sees, not how that system sees itself.
An excellent addition to the thread - thanks Terry.

Just trying to work out exactly what you mean in your last sentance.........I know it's me, hopefully it will click!
It is another way to say what I said above.

If you are within XP it will see XP as drive C:\ but Win7 as D:\, when you are within Win7 it will be seen as C:\ and XP will be seen as D:\. So when you make a change you have to remember which system you are in so you can make the changes accordingly. As making a change within XP will not get you the same results as making a change within Win7. therefor making a change could possibly have a negative effect.
sorry for my english!!Ihave something like that! I have installed xp 64 and than win7 64 on same partition.And now i cant boot only in win7.I want to have choices to boot from 7 or xp.What can i do??Thank you for understanding!!