how to lock a folder through windows application

If you right click a folder, then click advanced you can select 'Encrypt Contents'.

I've never used it so can't say much about how it works, but hope this is what you need.

via the command line
cipher /e /s:directory
cipher /e pathname

locking is not possible with tips and tricks but yes encryption is very well possible.

How encryption will be possible ???

I have encrypted it, but nothing happened...just changed the name color of folder from black to green
A dialogue box was open for some backup file and it need a password I have enter then it demand a file to export it in a file ...why ???

May be other user cant access it apart from administrator

Thanks ve3fa

Could it be possible that it needs password or not accessible in my login also ???

no it will always be available while logged into your account. Otherwise you need a 3rd party application i.e. folderlock

Thanks Experts