Try this i once had to do it and it worked for me i run Vista !
If you cannot set custom permissions, for files or folders, here are some things you can try, depending on your symptoms.
1) If the Security tab is not visible: If you can see only the Sharing tab and NOT the Security tab, check the Properties for that drive. The Security tab is visible only on NTFS drives and will NOT be visibly if you are using the FAT file system.
2) If Check marks disappear even after you have made and saved the changes:If you have set permissions and then apply them to anything, other than the default location, (this Folder, Sub-folder & Files) Windows Vista ( and 7) adds a check mark in the Special Permissions box. You can now view the applied permissions by clicking Advanced > Edit > selecting the User / Group > Click Edit. You may have to scroll to the bottom of the Permissions list to view it.
3) You find that the check marks for some users are shaded and in the Permissions dialog box, the check boxes for those users are unavailable: Such permissions are inherited from the folder in which the file/folder is stored, and not set explicitly. To break the inheritance chain, you have to, in the Security Tab, click 'Advanced' in the 'Advanced Security Settings' box, then click Edit and finally clear 'Include Inheritable Permissions From Objects Parent'.
4) If the Permission settings are not available: You need to check your user account rights. Are you logged in as a member of the Administrators group? Or are you the owner of the object, to set its permissions? If you are logged in as a Standard user, you will be able to view only your own permission settings. If you select another user / group on the Security tab, the permissions box would be unavailable.
Hope this sorts out your problems !
Edited by doinmeedin, 11 November 2009 - 06:29 AM.