As a big fan of open source software (this entire review was written in Open Office), we were hoping that TrueCrypt would give the pay products a run for the money not spent. Unfortunately, TrueCrypt is not whole drive encryption software as it was defined for this category. TrueCrypt can encrypt an entire drive; however, that drive cannot be the drive from which the operating system boots. TrueCrypt can encrypt external USB drives, flash drives and MP3 players, but it cannot encrypt the partition on which Windows XP resides.