In today's world we have all read about someone loosing a laptop or having it stolen with sensitive data that should never get out into "the wild". Well the solution to this problem is simple, whole hard disk encryption. That requires a password at boot-up to load the Operating System. As long as the computer is stolen/lost while its off it's pretty much impossible/impractical to crack any encrypted drive particularly if your password is strong.

I recommend TrueCrypt if you are looking for a great and easy solution to encrypt a standard desktop or laptop. It works with Windows, OS X and Linux also note that its Free and Open Source. I won't get into details about the software their website has great documentation and its very easy to use. Download the installer and follow the wizard to enrypt your entire hard drive.

What you don't want to do is install it and just create a encrypted virtual drive to store your “sensitive” files on, because windows creates all kinds of temporary files so opening a file might create a cached version on your system that is unencrypted. So simply put encrypt the whole hard drive will create a very secure environment that will keep your information secure.

I have only touched one feature that TrueCrypt provides, for most people it will be the only part of the software they will need but its a pretty full featured tool.