original: Most owners of zombie computers are unaware that their system is being used in this way.
simplifications: Owners of zombie computers don't know that their computers are used in this way. Owners of zombie computers aren't aware their systems are being used this way. Most victims of hackers are unaware their computer is being used by another person. Most owners of zombie computers have no clue that their computer is being used in this way. Most owners of zombie computers don't know their system is being used in this way. Most owners of zombie computers do not know their system is being used this way. Most owners are unaware there system is being used as a zombie computer. Most owners of zombie computers are unaware that it is being used this way. Most owners of zombie computers are not aware that their computer has a virus or has been hacked in some way. Most zombie computer owners are unaware that their system is being used in this way.