Some versions of Windows come with bitlocker. That encrypts the whole hard disk. That's very safe. But maybe you have another versionyou want only to encrypt ONE file ("a file"). If it's one file only, consider to store it unencrypted in a USB-stick that you guard with your life. That's very safe also. Or zip it to a password protected zip-file.
So please tell more.
Does anybody know a program to encrypt a file on my PC that is easy to use and free.