You can lock any folder without using any software.

Follow these steps.

1.Suppose you have a folder named abcd in D:\abcd.
2.In the same drive next to the folder create a new notepad 
file with the exact statement
ren abcd abcd.{21EC2020-3AEA-1069-A2DD-08002B30309D}
3.Now save this text file as loc.bat
4.Create another notepad file and type
ren abcd.{21EC2020-3AEA-1069-A2DD-08002B30309D} abcd
5.Save this as key.bat
6.Now there are two batch files . Double click loc.bat and your
folder will change into Control Panel and its contents cannot be viewed .
7.To open the folder double click key.bat and you get back your original folder .
8?For more safety keep the key.bat in another location .
Only for unlocking copy paste to the original location and double click .