TrueCrypt
Security has always been a big issue for PC user Sometimes you've even got to worry about those with access to your computer - such as friends, relatives or colleagues - "spying" on you. Want to protect your files from prying eyes? That's where TrueCrypt comes in.
TrueCrypt is an OpenSource software program that allows you to create an encrypted volume (in other words, a virtual data storage area). In this data storage area, you can put all the files you want, from photos to videos to text documents. The crypted volume will then be protected with a sophisticated cryptation algorithm that makes it impossible to see the contents if one doesn't have the password. One word of warning: make sure you write your password down somewhere because if you forget it, there will be no way to open the volume once encrypted.
TrueCrypt is an incredibly powerful program and may not be for the computing novice. It's compatible with Windows 2000, Windows XP, Windows Vista, Mac OS X and Linux.