Step 1: Open windows explorer then click on Tools
Step 2: Go to Folder Options
Step 3: Click on the View Tab.
Step 4: Scroll to the bottom and uncheck the option that reads "Use Simple File Sharing"
Step 5: This will allow you to see the security tab when viewing the properties of a file/folder.
Note that this will only work on Windows XP Professional. In Windows XP Home Edition, you will have to go into Safe Mode and do this.