Lock Folder is just a small app that uses the built in feature of Windows to lock a folder (Win XP or higher). No encryption or high security. Just enough to keep most people out and great to keep kids out of your personal stash.
No install, just run and drag and drop a folder on the dialog. Enter a password and the folder is locked. To unlock, drag and drop the locked folder on the dialog and enter the correct password and the folder will be unlocked. The folder CAN be accessed if you forget the password (as I said, not high security), but you'll have to do the research on how to gain access without the password yourself.