Lock a Folder in Windows XP without any Software:

Details:
This Trick will Make your Folder Invisble and it can't be seen even in Hidden Files and Folders.you can Make any Folder Invisible by simply changing the Path in the Command Line.(i.e...By Changing the Portion C:\abc to the Path of the Specified Folder)

Procedure:
•Make a Folder in C Drive & Name it as abc.
•Open Command Prompt(Start--->run--->cmd).
•Type attrib +s +h C:\abc and Press ENTER.
•To Make it Visible again,type attrib -s -h C:\abc.