Other way of locking a folder without using any software.
Lock
Create a new folder or use any already created folder which you want to lock. I am going to lock folder deadstring67 which is present on my desktop. To begin right click on the folder and rename it to deadstring67.{2559a1f2-21d7-11d4-bdaf-00c04f60b9f0} or yourfoldername .{2559a1f2-21d7-11d4-bdaf-00c04f60b9f0}.After renaming it you can see that the folder becomes locked and its icon changes.
folder yourfoldername -> rename to yourfoldername.{2559a1f2-21d7-11d4-bdaf-00c04f60b9f0}
ex.
folder deadstring67 -> rename to deadstring67.{2559a1f2-21d7-11d4-bdaf-00c04f60b9f0}
Unlock
In the previous step you locked a folder now i will teach you how to unlock the folder. To begin Open command prompt and then navigate to location where your locked folder is. My folder is placed on desktop so ill change working directory to desktop. So i will type cd Desktop to change directory to desktop. You can simply type cd /yourpath. After that type command ren deadstring67.{2559a1f2-21d7-11d4-bdaf-00c04f60b9f0} deadstring67 this commands rename it back to just deadstring67 and folder will become unlocked
run -> cmd -> cd Desktop -> ren yourfoldername .{2559a1f2-21d7-11d4-bdaf-00c04f60b9f0} yourfoldername
ex.
run -> cmd -> cd Desktop -> ren deadstring67.{2559a1f2-21d7-11d4-bdaf-00c04f60b9f0} deadstring67