CRYPTOEXPERT 2009 LITE Free on the fly drive encryption system.
EditByBSEditor: CryptoExpert creates encrypted virtual disks and these disks are visible as usual disks with drive letters (for example, G:, H:, Z:, i.e. with any drive letter that is not used by other system devices). The data stored on a CryptoExpert disk is stored in the container file. A container is a file, so it is possible to backup a container, MOVE or copy it to other disk (CD-ROM or network, for instance) and continue to access your encrypted data using CryptoExpert. Any free drive letter (or choosen letter) in the system may be used to mount and to open an encrypted file-container for access. When the Virtual Disk is opened, you can read and write data as if it were a conventional removable disk. You can do anything with a CryptoExpert virtual drive that you can do with a normal hard drive; only that with CryptoExpert, the encrypted volumes require password authentication before the files become accessible.

Features:

Using powerful encryption Algorithm to encrypt your data: CAST 128 bit
Ability to Create encrypted containers (files vault) up to 20 Megabytes in size
Access to your files on virtual volume on the fly
Mapping any free drive letter like G:, F:, K: for virtual volume
Requires password authentication before the files become accessible
Works with all Windows application - even DOS applications
Really Fast
Looks like normal hard drive
Freeware! you can free download CryptoExpert 2009 Lite 7.10.0 now.