Lets lock a folder using notepad trick
which is named as PICS in your D: drive , whose path is D:PICS
Then the code should be something like this:
ren pics pics.{21EC2020-3AEA-1069-A2DD-08002B30309D}
Pics is your folder name. Use the name of the folder in place for pics. Save the text file as lock.bat in the same drive.


To unlock this locked folder:
Open another new notepad text file and type the following:
ren pics.{21EC2020-3AEA-1069-A2DD-08002B30309D} pics
 
Save the text file as key.bat in the same drive. Here again, pics is the name of the folder. Change it to the folder name you want to lock it.