WinXP 32bits + WinXP 64 bits dual boot

Archived from groups: microsoft.public.windowsxp.customize (More info?)

Hi,
I'd like to setup my Athlon 64 desktop to have dual boot between my legacy
32 bit WinXP and WinXP 64 bits. I'd some problems with my network card driver
in the 64 bit edition, and also with some software, and that's why I'd like
to have the 64bit edition for testing and the 32bit edition for "working".
I've partitioned my hard disk with two primary partitions. The first is
where I installed the 64bit edition, and the second where I've the 32bit one.
Here is the boot.ini file installed bye the 32bit winxp (the second option
which I assume is for the 64bit edition, does not actually boot that
installation):

[boot loader]
timeout=10
default=multi(0)disk(0)rdisk(0)partition(2)\WINDOWS
[operating systems]
multi(0)disk(0)rdisk(0)partition(2)\WINDOWS="Microsoft Windows XP
Professional" /fastdetect /NoExecute=OptIn
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP
Professional" /fastdetect

Any help?