I have a MacBook and for the past couple months I can not send any emails with an attachment because my computer tells me " your attachment contains a virus and can not be sent" I have tried sending a word document through my gmail, my hotmail, and even my mac email and it tells me the same thing. I don't know how to solve this problem. My screen also flickers all the time. I have spoken to apple tech support and they didn't know what to tell me. I could use any advice as to how to solve this problem, or what virus software to download. Thanks a bunch!