I have had scenarios similar to that, Floor9, one lady told me that she always gets viruses....so I asked her what she does online normally, she said she emails and plays games on some weird website...so I researched the website and tons of sources said it was covered in malware. I told her this and she goes "that can't be it, I'm on that site all the time! I always play games on that site!"
Uhh.... HELLOOOOOOO!? You always get on this site......and you always have viruses......
Why do you not see the correlation??
I ended up telling her to go to geek squad, because I wasn't qualified for the task (in my mind, I was replacing "qualified" with "patient enough")