WinFileCrypt is a simple free Win32 application to encrypt and checksum files of any size. It does not require any installation and can be run from an USB and uses 3DES cipher-block-chained encryption, with a 128 bit key. It is very simple to protect your personal and confidential files with this encryption program.
You can drag and drop file names to the application, specify the encrypt key and then click the button to encrypt the file.
When you want to decrypt the file, you need to specify the key provided while decrypting. Sine this application does not require any install, you can send the encrypted files in email as well.
WinFileCrypt is a very simple utility and if you are trying out encryption, please take a back up of the original file.