Encrypting File System (EFS) is a feature of Windows that you can use to store sensitive information on your hard disk in an encrypted format. Encryption is the strongest protection that Windows provides to help you keep your information secure.
Some key features of EFS:
Encrypting is simple; just select a check box in the file or folder's properties to turn it on.
You have control over who can read the files.
Files are encrypted when you close them, but are automatically ready to use when you open them.
If you change your mind about encrypting a file, clear the check box in the file's properties.
For Step by Step instructions on using EFS in Windows 7, please follow the steps found in this Microsoft Technet Video
Note: EFS is not fully supported on Windows 7 Starter, Windows 7 Home Basic, and Windows 7 Home Premium.
ITS offers an Encryption Service to assist users in setting up Windows7 Bitlocker.