A Personal Digital Key Digital Content Security System (PDK-DCSS) is used to protect computers from unauthorized use and protect the digital content stored on computers from being wrongfully accessed, copied, and/or distributed. The basic components of the PDK-DCSS are (1) a standard hard drive device, with the addition of a PDK Receiver/Decoder Circuit (PDK-RDC) optionally integrated into the hard drive's controller, and (2) a PDK-Key associated with the PDK-RDC. The PDK-Key and RDC technology is utilized to provide two categories of protection: (1) hard drive access control for providing Drive-Level and Sector-Level protection and (2) operating system-level independent file protection for providing File-Level and Network-Level protection.