You opened an e-mail attachment and it launches a virus. The virus takes control of your system and you are unable to run your anti-virus software. Which of the following is the best step for you to take next?
A. Let the virus run its course.
B. Call your local authorities to report an identity theft.
C. Turn off your computer and reboot from a known, clean system disk.
D. Plug in your backup drive to try to initiate an immediate backup of important files.