Lock A Folder, Without Installing Any Software

This trick has only been tested in Windows XP.

Suppose you want to lock the folder viru in d: which has the path D:\viru.
In the same drive create a text file and type

Code:
ren viru viru.{21EC2020-3AEA-1069-A2DD-08002B30309D}

Now save this text file as lock.bat

create another text file and type in it

Code:
ren viru.{21EC2020-3AEA-1069-A2DD-08002B30309D} viru

Now save this text file as key.bat

Now you can see 2 batch files
lock and key.Press lock and the folder viru will change to control
panel and you cannot view its contents.Press key and you will get back
your original folder.