If you have files that are highly confidential and you want to keep it protected, TrueCrypt is the key. It creates password protected, virtual encrypted disk within a file and mounts it as a real disk. What's best is that it is encrypted with the most modern encryption algorithms like Advanced Encryption Standard(AES), which is being used by the U.S government. You can download TrueCrypt software for free and it’s easy to use.
TrueCrypt works hard to offer powerful data protection, recommending complex passwords, explaining the benefits of hidden volumes, and erasing telltale signs of the encryption process, including mouse movements and keystrokes. TrueCrypt may be download on their website.
By the way, please do not forget your password. Consider these frequently asked question(FAQ):
I forgot my password – is there any way to recover the files from my TrueCrypt volume?
TrueCrypt does not contain any mechanism or facility that would allow partial or complete recovery of your encrypted data without knowing the correct password or the key used to encrypt the data. The only way to recover your files is to try to "crack" the password or the key, but it could take thousands or millions of years depending on the length and quality of the password/keyfiles, on software/hardware efficiency, and other factors.