How to create a bootable USB thumb drive for Windows 7 64bit using Windows XP 32bit machine.

Problem:
We have the ISO of the Windows 7 64bit and want to install it using the USB Thumb drive installation method.
We have access only to our old Windows XP 32bit OS.

Solution:
Use the standard MS tool to format the USB Thumb drive [1].
It will failed at the 100% with an error message saying:


Status: Files copied successfully. However, we were unable to run bootsect to make the USB device
bootable. If you need assistance with bootsect ....#truncated#


Download and install the EasyBCD for your WinXP 32bit [2].
The installation will copy the bootsect.exe tool that can be used on winXP.

Run the bootsect.exe to make the USB Thumb drive bootable. The 'E:' is the driver letter assign by your XP!

C:\Program Files\NeoSmart Technologies\EasyBCD\bin>bootsect.exe /nt60 E:
Target volumes will be updated with BOOTMGR compatible bootcode.

E: (\\?\Volume{ba063d8e-7111-11e0-b640-aafb6b9edf9e})

    Successfully updated NTFS filesystem bootcode.

Bootcode was successfully updated on all targeted volumes.

As last, unmount the USB, reboot the system, change the BIOS and start the installation.

References:

[1] Windows 7 USB/DVD Download Tool

[2] EasyBCD

For troubleshooting purposes:
How To Boot And Install Windows 7 From USB Flash Drive