This is a real problem, nobody thinks that can be victim of a computer crime until it is. There is a big problem relating to the people thinking about this kind of attacks.
Computer crimes can be very important and can make great damage to enterprises.
Computer Crime will decrease once people begin to think about the Risks and begin to protect their systems from the most common attacks.

Copying sector by sector at the bit level provides the capability to
examine slack space, undeleted clusters and possibly, deleted files.
With answer a, only the system files are copied and the other
information recovered in answer b would not be captured.
Answer "Copying the disk directory" does not capture the data on the disk, and answer
"Copying and authenticating the system files
" has the same problem as answer "Copying the system files". Actually, authenticating the system files is another step in the computer forensics process wherein a message digest is generated for all system directories and files to be able to validate the integrity of the information at a later time. This authentication should be conducted using a backup copy of the disk
and not the original to avoid modifying information on the original.
For review purposes, computer forensics is the collecting of information from and about computer systems that is admissible in a court of law.

The risk assessment is critical because it enables the person responsible for contingency planning to focus risk management efforts and resources in a prioritized manner only on the identified risks. The risk management process includes the risk assessment and determination of suitable technical, management, and operational security controls based on the level of threat the risk imposes. Business units should be included in this process. Source: SWANSON, Marianne, & al., National Institute of Standards and Technology (NIST), NIST Special Publication 800-34, Contingency Planning Guide for Information Technology Systems, December 2001 (page 7).

The preventive/technical pairing uses technology to enforce access control policies.
TECHNICAL CONTROLS
Technical security involves the use of safeguards incorporated in computer hardware, operations or applications software, communications hardware and software, and related devices. Technical controls are sometimes referred to as logical controls.
Preventive Technical Controls
Preventive technical controls are used to prevent unauthorized personnel or programs from gaining remote access to computing resources. Examples of these controls include:
* Access control software.
* Antivirus software.
* Library control systems.
* Passwords.
* Smart cards.
* Encryption.
* Dial-up access control and callback systems.
Preventive Physical Controls
Preventive physical controls are employed to prevent unauthorized personnel from entering computing facilities (i.e., locations housing computing resources, supporting utilities, computer hard copy, and input data media) and to help protect against natural disasters.
Examples of these controls include:
* Backup files and documentation.
* Fences.
* Security guards.
* Badge systems.
* Double door systems.
* Locks and keys.
* Backup power.
* Biometric access controls.
* Site selection.
* Fire extinguishers.
Preventive Administrative Controls
Preventive administrative controls are personnel-oriented techniques for controlling people's behavior to ensure the confidentiality, integrity, and availability of computing data and programs. Examples of preventive administrative controls include:
* Security awareness and technical training.
* Separation of duties.
* Procedures for recruiting and terminating employees.
* Security policies and procedures.
* Supervision.
* Disaster recovery, contingency, and emergency plans.
* User registration for computer access.
Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the
Ten Domains of Computer Security, 2001, John Wiley & Sons, Page 34