If you have Windows XP, and your hard drive is formatted as NTFS, you can set permissions on files so that only users you specify can access them. However, if your Windows XP computer is not part of a Domain on a network, you may notice that there is no Security tab when you right-click a file and choose Properties. For some reason, the default for Windows XP computers that are part of a Domain is to have that visible.
For Windows XP computers that are not part of a Domain (they are stand-alone, or part of a workgroup), the default is to have the Security tab hidden.
Follow three simple steps:
Open Windows Explorer, and choose Folder Options from the Tools menu.
On the View tab, scroll to the bottom of the Advanced Settings and clear (click) the check box next to "Use Simple File Sharing."