what os are you running and do you keep up on the security fixs for it?
Bukhari:V3B48N826 “The Prophet said, ‘Isn’t the witness of a woman equal to half of that of a man?’ The women said, ‘Yes.’ He said, ‘This is because of the deficiency of a woman’s mind.’”
maybe the "hacker" has done atrojan , in thuis case there is no AV that will recognize the trojan .. try for firewall , i usualy use the " zone alarm " , if u have somefile that u dont know what is this accessing the internet , disable his access and i think that then the hacker will can not connect to u