Vista Tutorial - How do I Prevent Access of certain Folders on External USB drive

I wish to prevent access to certain folders on the extrenal drive , in such a
way that among 3 computers it is only accesible from one.

for a scenario:
"MyDocs Copy" should not be accesible while the music/pictures should be

note all systems users can be admin/standard account

so setting Admin access only - serves no purpose.. as it is external and
accesible from other pc, where someone else can have an admin account.
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Also I need to stop the autorun from running on a newly connected computer.

Encrypt the folder/file with EFS from the computer you want to be able to access it (be sure to back up certificate). This will allow only the system/user who created it to access it.