I believe that Kaspersky is an excellent anti virus system. All antivirus programmes have back doors.
Most often hackers, pirates and viruses gain access to a computer through the fault of the user, downloading malware. An antivirus programme will not prevent you from downloading what you want.
I suggest that you computer is infected. If you wish for me to tell you what is infected, what is the malware and how to disinfect your machine, let me know. But I would keep on with Kaspersky. That's I have been using for years.
CCM Moderator and Virus/Security Contributor