You will have to do it this way:
1.attach the external usb drive
2. Make sure the drive is initialised to mbr and create at least one primary
partition - big enough to hold windows - 50gb is plenty.
3. Mark the primary you just created on the external HD Active - this is vital.
We are going to apply the install.wim - you still have that I presume - .iso not used in this method.
Run as admin the run-me-as-admin.cmd in this: WIN678-INSTALLER.zip
It will tell you what to do as you go along.
When it has done:
Do not try and boot it from the other machine. Shut down the other machine, remove the HD from the enclosure and put it in your lappie.
Should be fine - note your vista drive letter will be D not C - don't worry that is fine.
PS , what are planning to do about a product key if you can't read the one off the sticker?