How can I apply a password to a folder?

Hello,

I am pretty confused as goes for all this subfolder security and permmisions
stuff.

I have 4 computers connected to a linksys hub of which only three of them
are using an rj45 cable and bywhich the laptop computer connects wirelessly
by rf to the linksys hub.

The two computers I am concerned about is the laptop connected to a linksys
hub by rf and the server desktop connected to the same linksys hub.

Is it possible for that only the laptop can have access to a particular
subdirectory
on the server, by using some sort of security settings in Windows. All other
computers should not have access to this subdirectory!

Bare in mind the laptop has XP and the server has Vista.

All feedback or orientation to information showing how to do this is greatly
appreciated.

--
Best regards
Roberto