How to Set a Password on a Shared Folder in Vista
- 1). Use your mouse to right-click on the folder that you would like to password-protect.
- 2). Select "Properties" from the drop-down menu and then select the "Security" tab in the new window that pops up.
- 3). Select "Edit" to change the security settings.
- 4). Choose the users whom you would like to keep out of the folder. Select their names from the "Group or User Names" list.
- 5). Check the "Deny" checkbox beside the "Modify" option, under the "Permissions for Users" section.
- 6). Select "OK" and then "Yes" when the security warning window opens to finalize the changes. Now the selected users will not be able to access that folder without your user account password.
Source...