Lock Files & Folders XP can lock entire folders or individual files with ease. By locking; it actually makes and entire folder/file inaccessible to any program, and also they cannot be deleted, renamed or anything of the kind.
SafeHouse provides transparent on-the-fly hard drive encryption for your PC. Using SafeHouse, you can allocate portions of your existing hard drives to be reserved for encrypted data. SafeHouse appears to Windows as another drive letter.
File Tutelary is a shareware to encrypt files and decrypt files by your own password quickly and securly.
You can encrypt any file with a password so your documents are kept safe away from prying eyes.
SecretSpace is a utility that allows you to conceal short messages invisibly within plain text documents. It does this by inserting superflous spaces in between words. This can be used to exchange secret messages.